[GMCnet] new engines for the GMCs

[Mike Sadlon]

Some of you may be following this from the Facebook page. I have been looking into the viability of the LS engines for GMC motorhomes. Problem number
one was getting the LS engine to hook to our 425 transmissions. The Panrail on the LS interferes with our differential. I solved the connection
problem by rotating the transmission up about 25°. That allows clearance around the Panrail and diff. The next problem was the transmission now
interferes with the step area. It could be worked around but it illuminates a True Bolt-in situation. I have identified an aftermarket block that
would get us 427 in.³ relatively easily. And still fit in the stock location. The target for the horsepower of this engine would be 450 HP and 500
pounds of torque. They can have late-model fuel injection and coil on plug spark system. I'm ready for questions

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[James Hupy]

Wonder how a tm 425 will like 500 foot pounds of torque? Probably not much,
I expect.
Jim Hupy
Salem, Or
78 GMC ROYALE 403

[Justin Brady]

So what are you going to do about the step? move it back a foot and lose the floor space?

Call me what you will, but that level of modification is not going to appeal to anyone but someone with a completely gutted project coach.

--
Justin Brady
http://www.thegmcrv.com/
1976 Palm Beach 455

[Mike Sadlon]

It does not need to go back it needs to go up about 2 inches to clear the rear of the transmission

[Justin Brady]

Gotcha, thats not terrible, you could simply build a small cowl to cover it.

--
Justin Brady
http://www.thegmcrv.com/
1976 Palm Beach 455

[Mike Sadlon]

The new engine does not need any modifications To the coach. The motor will need a new front mount , custom oil pan new exhaust.

[Mike Sadlon]

From all of my research the stock numbers were 330 to 350 HP. And 450 to 500 torque. The new engine would have a little more horsepower because of
the ability to Rev up a little freer. We could make more horsepower and torque but this is the goal of the combination

[Jim Kanomata]

Apparently, your not aware that the Big block Chev engines have been
adapted to the 425 trans by many.
It works well once it is done correctly.
The 425 trans, when slighty modigied and proper parts used like the ones
Manny T does for me. My Cad 540 with Twin turbo,Intercooled,port injected
has been holding up with over 80,000 miles.
You need to know that I have been around mods on these since 1980 and have
rubbed shoulders and exchanged info with them.

--
Jim Kanomata
Applied/GMC, Fremont,CA
ji...@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502

[John R. Lebetski]

The 70 Eldorado E car had similar HP and Tq so that is not an issue. I just don't think a low nickel BB Chevy (if that's what you are suggesting) will
have the longevity of the Olds, but that will he offset by availability.
--
John Lebetski
Woodstock, IL
77 Eleganza II

[Hal StClair]

Great motors and can be built to make more power than could ever be used in our rigs. Modifying the oil pan is no trivial matter though as they are a
structural element of the block. The poor ol' 425 is kind of out of place though with about half the gears you'd like. It can be built robustly enough
to take the guff though so thats an easy problem to contend with. I am quite curious how your final drive and half shafts would fit-probably need
custom length shafts at the least IF the angles can be made to work. The raised step is a non issue IMO and a really simple thing to deal with. You
would have to deal with the electronics as well which isn't too bad, either custom made or home built depending on your abilities.
Would probably be a fun project but not for the faint of heart. $$$ is the big thing on a project like this as well as 'stick-with-it-ness' to see it
through to the end.
Hal
--
1977 Royale 101348,

1977 Royale 101586, Diesel powered,

1974 Eagle Bus 45',w/slideout

[Mike Sadlon]

I know the big blocks have been installed. But I don't believe there's any combination of intake that will let it fit underneath the stock engine
cover. If I remember correctly even Daves 8.1 has a raised hatch

[Hal StClair]

JohnL455 wrote on Thu, 20 April 2017 13:32

> The 70 Eldorado E car had similar HP and Tq so that is not an issue. I just don't think a low nickel BB Chevy (if that's what you are suggesting)
> will have the longevity of the Olds, but that will he offset by availability.

These are modern motors either all aluminum or iron block versions, that are typically good for 200,000 miles or more. Great platform in most
applications, Corvettes, trucks, rear drive cars etc. Same bore spacing as the old small block Chevy but nothing else carried over. All had aluminum
heads, composite intakes. 4.8l,5.3l,5.7l,6.0l,6.2l,7.0l sizes stock with lots of aftermarket support. All aluminum versions were in the 440lb range
which is a real plus.

Hal
--
1977 Royale 101348,

1977 Royale 101586, Diesel powered,

1974 Eagle Bus 45',w/slideout

[Mike Sadlon]

Just so everyone understands. There are two things going on here. First is the LS conversion. The diff stays in at stock location then there is an
adapter to rotate the transmission 25°. Then there is another adapter to rotate the engine back 25° so what is level. The goal was a kit to be able
to put a junkyard 6.0 LS engine into one of our coaches. New transmission pan new oil pan new front mount And a transmission mount. The goal for the
kit price point was under $2000. The rotated engine with a low profile intake should fit under the Hatch. But the rotated transmission will not fit
underneath the step.

[Mike Sadlon]

The other is a brand-new engine block available from world products small block lower LS cylinder heads. It's a hybrid they created. I have prices
for a completed short block. Working on the pricing to build a complete engine.

[Mike Sadlon]

The small block lower only needs a oil pan and front mount to make it work everything else stays in the stock location. These blocks have already
built to handle over 800 HP. Considering the quality of the parts that you have to use on this aftermarket combination, our 450 horse will last a
very very long time

[Mike Sadlon]

Over the last week as I've starting the pricing on this, I was hoping to be able to build assembled motor ready to go with exhaust for under 10 grand.
My first quote on the short block balanced and assembled is over $5000. And it's looking like it would need to be closer to $12,000 to be done with
computer ready to Run.

[Jon Roche]

I really dont know a thing. Other then being around 6.0 ls conversions in grand wagoneers. Prefect for those, but I just dont get how that
junkyard engine can pull around our coaches. Works perfect for the wagineers, but we are twice the weight. Must be some more performace upgrades
you had in mind other then taking a stock tahoe engine and putting it onto the 425? And at what price?
--
Jon Roche
75 palm beach
St. Cloud, MN
http://lqqkatjon.blogspot.com/

[Mike Sadlon]

The 6.0s and 6.2 have been the go to motor in the 1 tons since the demise of the 8.1. And their GVW's are way above ours. The 6.0s what outwork the
Ford V10's in our service Fleet.

[Ronald Pottol]

Has anyone looked into a lock up torque converter? It ought to help freeway
milage. They make them for the TH-400

Great to hear of some cheaper motor options, I'd love Manny's diesel, but
I'd love to keep the extra $20-30k in my pocket.

[Hal StClair]

Like I mentioned, great motors but they need rpm for the towing you're talking about. To get to our weight levels you would probably need a 4.1 gear.
At that rpm your economy wouldn't be much different than the present combination. You might be up with Manny's kit for money expended.

Hal
--
1977 Royale 101348,

1977 Royale 101586, Diesel powered,

1974 Eagle Bus 45',w/slideout

[David H. Jarvis]

Wasn't there a problem with 454 engines and rear bearings?

[Hal StClair]

Ronald Pottol wrote on Thu, 20 April 2017 15:43

> Has anyone looked into a lock up torque converter? It ought to help freeway
> milage. They make them for the TH-400
>
> Great to hear of some cheaper motor options, I'd love Manny's diesel, but
> I'd love to keep the extra $20-30k in my pocket.
>

> On Apr 20, 2017 13:57, "Mike Sadlon" wrote:
>
> > The 6.0s and 6.2 have been the go to motor in the 1 tons since the demise
> > of the 8.1. And their GVW's are way above ours. The 6.0s what outwork the
> > Ford V10's in our service Fleet.
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
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> >
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You need to look at it apples to apples. Manny's kit with motor out the door vs an LS with new motor OTD. Or see if you can source your own 6.5 and
buy Mannys kit (if he's interested in selling it that way) vs this LS 'kit' and used engine. The labor to install either engine would probably be
close either your own or paying someone. JMT

Hal
--
1977 Royale 101348,

1977 Royale 101586, Diesel powered,

1974 Eagle Bus 45',w/slideout

[Matt Colie]

Harry wrote on Thu, 20 April 2017 17:49

> Wasn't there a problem with 454 engines and rear bearings?

Please don't get me going on the 454...
There is a real good reason that they are out of production.
The only reasons the 8.1 is gone is that it was too expensive for Government Motors to sell and they were looking to end gas engine production.

Matt - the refugee of Detroit eco-wars.
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Still Loving OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit

[Kerry Pinkerton]

Mike, first of all, I applaud your effort. If folks didn't ask 'what if', we'd still be riding horses. Go for it. I've thought of the same kinds of
things myself.

A few questions/comments.

1- What happens in the tranny when you rotate the pan so it's no longer level? Will there be any issues with fluid pickup etc? Manny is your go-to
source for questions about that.

2- I have a 6.0 in my '07 GMC Serria pickup. It has a 3.70 final drive and it will indeed make a lot of power but it makes it at 4000-6000+ RPM.
With a 425 and 3.70 final drive, you're still going to be at 3000 rpm at 60mph and I don't know if that is the sweet spot for LS torque.

3- Hal StClair did a masterful job installing a diesel with motor tranny in his Royale. What he did was use the entire tranny and front wheel drive
system from a 1 ton 4wd. Not anywhere like a kit that you are thinking about but he has a modern overdrive 5 speed tranny and a final drive that fits
the motor. The RWD portion is blocked off at the tranny. The 425 is the major problem with updating the GMC imo.

4- What about rotating the MOTOR instead of the tranny? The fuel injection shouldn't care but you'd probably have to modify the oil pickup and still
modify the oil pan.

5- From a kit standpoint, raising the hatch is much more viable than modifying the step for most folks.

Just a few thoughts from another fabricator.


--
Kerry Pinkerton - North Alabama

77 Eleganza II, 403CI, Manny Brakes, 1 ton, tranny, lots of aluminum goodies.

http://www.bdub.net/pinkerton/

'03 Fleetwood Discovery 39L

[D C _Mac_ Macdonald]

That 6.0 is still moving my 1999 GMC Sierra 2500 down the road quite well. Has also hauled a 4-ton travel trailer quite well, also. About 176,000 on the clock so far.


Rated HP was rated 300 @ 4800. Torque was rated 355 lb-ft; no RPM stated. Even that should move a GMC MH quite well.


~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
~~ ~ D C "Mac" Macdonald ~ ~~
~ ~ Amateur Radio - K2GKK ~ ~
~ ~ Since 30 November '53 ~ ~
~ ~ USAF and FAA, Retired ~ ~
~ Member GMCMI and Classics ~
~ ~ ~ Oklahoma City, OK ~ ~ ~
~~ ~ ~ "The Money Pit" ~ ~ ~~
~ ~ ~ ~ TZE166V101966 ~ ~ ~ ~
~ ~ ~ '76 ex-Palm Beach ~ ~ ~
~~ k2gkk + hotmail dot com ~~
~ www.gmcmhphotos.com/okclb ~
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
______________
|[ ]~~~[][ ][]\
"--OO--[]---O-"



________________________________
From: Gmclist <gmclist...@list.gmcnet.org> on behalf of Jon Roche <lqqk...@gmail.com>
Sent: Thursday, April 20, 2017 15:50
To: gmc...@list.gmcnet.org
Subject: Re: [GMCnet] new engines for the GMCs

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[A.]

Hal StClair wrote on Thu, 20 April 2017 16:46

> Like I mentioned, great motors but they need rpm for the towing you're talking about. To get to our weight levels you would probably need a 4.1
> gear. At that rpm your economy wouldn't be much different than the present combination. You might be up with Manny's kit for money expended.
> Hal

And nobody ever seems to pay attention to the fact that the belt driven stuff hanging on the engine turn 34% faster with a 4.11 final drive from the
OEM 3.07.

If you don't change pulley diameters to compensate, you will need alternator, AC compressor, power steering and water pumps, not to mention belts, 34%
more often.
--
73 23' Sequoia 4 Sale
73 23' CanyonLands Parts Unit 4 Sale
Upper Alabama
"When I grow up I am going to be a curmudgeon."

[Rob Mueller]

Jim,

Well in Dave Lenzi's 8.1 Vortec powered Royale it likes 450 ft lbs.

http://www.gmcmhphotos.com/photos/aa-miscellaneous-photos/p36474-d-lenzi-27s
-81-front-frame.html

http://www.gmcmhphotos.com/photos/aa-miscellaneous-photos/p52884-dyno-run-vo
rtec-81.html

Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808

-----Original Message-----
From: Gmclist [mailto:gmclist...@list.gmcnet.org] On Behalf Of James
Hupy
Sent: Thursday, April 20, 2017 1:54 PM
To: gmc...@list.gmcnet.org
Subject: Re: [GMCnet] new engines for the GMCs

Wonder how a tm 425 will like 500 foot pounds of torque? Probably not much,
I expect.
Jim Hupy
Salem, Or
78 GMC ROYALE 403

[Rob Mueller]

Mike,

Have you determined if the axle from the final drive to the passenger side
clears the main bearings and crank / rod throws?

Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808


-----Original Message-----

From: Gmclist [mailto:gmclist...@list.gmcnet.org] On Behalf Of Mike
Sadlon
Sent: Thursday, April 20, 2017 1:50 PM
To: gmc...@list.gmcnet.org
Subject: [GMCnet] new engines for the GMCs

Some of you may be following this from the Facebook page. I have been
looking into the viability of the LS engines for GMC motorhomes. Problem
number
one was getting the LS engine to hook to our 425 transmissions. The Panrail
on the LS interferes with our differential. I solved the connection
problem by rotating the transmission up about 25°. That allows clearance
around the Panrail and diff. The next problem was the transmission now
interferes with the step area. It could be worked around but it illuminates
a True Bolt-in situation. I have identified an aftermarket block that
would get us 427 in.³ relatively easily. And still fit in the stock
location. The target for the horsepower of this engine would be 450 HP and
500
pounds of torque. They can have late-model fuel injection and coil on plug
spark system. I'm ready for questions

[Mike Sadlon]

You guys are so good, but nobody has asked a question I haven't though about.

First lets do the general question about moving down the road, then I will address Kerry's excellent questions.
It takes X amount of energy to move Y mass vs drag/ mechanical load. It's why we get the same mileage no matter what gear we put in. The ls motors at
best are 5-10% more mechanically efficient than the 455. That's less than 1 mpg. If I find a way to get around basic physics, I won't ever hang with
you guy again, I'm going into space.

That being said, it takes around 100-125 HP (some smart peoples best guess. For reference my HHR SS only needed 40 hp to run 80 mph)to move our
coaches done the road. So if we had only 125, it might run 65, but it would take days to get there. So, as long as we stay in a range where the motor
can make 100 hp we will move down the road. Extra HP just makes it more fun to get there. The nice thing is modern fuel injection will figure that out
for us.

So the short answer is it will be fine, any gear you run. Look at your trucks, it will pull down the road that 4 ton trailer at 1800 rpm until you hit
a hill and need more power. Then it adds fuel until it can't compensate, then it down shifts.

[Kerry Pinkerton]

Mike S wrote on Thu, 20 April 2017 18:08
> ...

> It takes X amount of energy to move Y mass vs drag/ mechanical load. It's why we get the same mileage no matter what gear we put in. The ls motors

> at best are 5-10% more mechanically efficient than the 455. ...

>
> So the short answer is it will be fine, any gear you run. Look at your trucks, it will pull down the road that 4 ton trailer at 1800 rpm until you
> hit a hill and need more power. Then it adds fuel until it can't compensate, then it down shifts.

I'd tend to agree. Our diesel pusher has 330 HP and 850 ft lbs of torque. I have an aftermarket product that hooks into the coach computers and
displays lots of stuff including HP and torque in real time. Even with a 26000 (empty) coach with the aerodynamics of a concrete block, it takes less
than 100 HP and 250 ft lbs of torque to maintain 55 on flat ground. Hit a hill and both numbers and gallons/minute of fuel rate go up and the 6 speed
Allison downshifts if the RPM gets down near the peak torque RPM (1550 RPM)...depending on which transmission mode I'm in.

My concern is how much torque the 6.0 (LS) has at 2500 RPM without a smart tranny and lots of gears and a lockout converter. While I can assure you
that my 1/2 ton with the 6.0 will cruise at 60 at 1500 (or less), as SOON as I hit a hill, the RPM goes up either because the lockout converter
unlocks or it downshifts. It's so smooth you can't tell unless you're watching the readouts but it does. The thing is, I don't know what it would do
if there was a way to hold it at 2000 RPM and try to accelerate without downshifting. I'm suspecting not that well but probably at least as good as
my 403. I also get about 18-19 on the highway. BUT, if I put any load on it due to a trailer the mileage tanks. Even an empty flatbed car hauler
(weights about 2000 lbs)causes mileage to drop to 10 mpg. Put a car on the trailer and expect 5-6 mpg. It will still skoot with the weight but might
go to 3rd at 60 and 5500 RPM which just ain't gonna happen with a 425 behind it.

--
Kerry Pinkerton - North Alabama

77 Eleganza II, 403CI, Manny Brakes, 1 ton, tranny, lots of aluminum goodies.

http://www.bdub.net/pinkerton/

'03 Fleetwood Discovery 39L

[Mike Sadlon]

kerry pinkerton wrote on Thu, 20 April 2017 17:09

> Mike, first of all, I applaud your effort. If folks didn't ask 'what if', we'd still be riding horses. Go for it. I've thought of the same
> kinds of things myself.
>
> A few questions/comments.
>
> 1- What happens in the tranny when you rotate the pan so it's no longer level? Will there be any issues with fluid pickup etc? Manny is your

> go-to source for questions about that. The trans rotates around the diff centerline. the new pan just need to maintain the same effective level from
> the centerline, and volume. It will take a custom pickup.

>
> 2- I have a 6.0 in my '07 GMC Serria pickup. It has a 3.70 final drive and it will indeed make a lot of power but it makes it at 4000-6000+ RPM.

> With a 425 and 3.70 final drive, you're still going to be at 3000 rpm at 60mph and I don't know if that is the sweet spot for LS torque. The ls
> motor has one of the flattest toque curves out there. it will make all the power you need at any rpm. Hook a trailer to that truck and it will still
> run down the road in OD.

>
> 3- Hal StClair did a masterful job installing a diesel with motor tranny in his Royale. What he did was use the entire tranny and front wheel
> drive system from a 1 ton 4wd. Not anywhere like a kit that you are thinking about but he has a modern overdrive 5 speed tranny and a final drive

> that fits the motor. The RWD portion is blocked off at the tranny. The 425 is the major problem with updating the GMC imo. Yes, I have followed
> Hal's build and he indeed do a masterful job. But it as far from a bolt-in as you can get. I would like a kit where average skills could install.
> And I agree about the trans, we don not have reasonable trans option. But I believe we have reasonable engine options.

>
> 4- What about rotating the MOTOR instead of the tranny? The fuel injection shouldn't care but you'd probably have to modify the oil pickup and

> still modify the oil pan. I looked at that as I was rotating the engine around to find a balance that I thought would work. That combination
> required require the motor to be at about a 40 degree angle. I just don't think the average customer would accept that.
>
> 5- From a kit standpoint, raising the hatch is much more viable than modifying the step for most folks. I agree whole heartedly. It was Jeff Sirum
> who pointed the step issue. I was just about to mock it up on the frame he provided to me. The valve cover and intake and hatch are within an inch
> of each other. I would gladly give the step for hatch. I hope I can fab a bolt in part for the step.
>
> Just a few thoughts from another fabricator. It was great meeting you in Dothan.

[Kerry Pinkerton]

BTW, I'm so glad you're discussing this here. I'm just not going to get into a technical discussion on FB. In addition, there are many, many very
knowledgeable folks here that simply do not, and will never do FB.

--
Kerry Pinkerton - North Alabama

77 Eleganza II, 403CI, Manny Brakes, 1 ton, tranny, lots of aluminum goodies.

http://www.bdub.net/pinkerton/

'03 Fleetwood Discovery 39L

[Mike Sadlon]

Well that didn't work as planned.
I though my answer to Kerry where going to be in RED.
OK so read it carefully.

[Hal StClair]

As I keep expressing, I'm a big fan of LS motors. I swapped an LS6 into my 1965 Vista Cruiser, have a 402ci LS stroker in a 1963 Corvette and my Chevy
half ton has one as well. As Kerry states, they are fine on the level but load them at low rpm and they tank on low end torque and mileage goes into
the toilet. Its not an issue about enough HP it's torque that really does the work.
I still think your oil pan mods will be a real tough nut to crack. The LS is a deep skirt block and the oil pump is located up front so the pickup
runs to the rear through the pan. Just a quick look at mine and I see a real issue getting the right half shaft under the pan. Maybe using a dry sump
system could get you the clearance but even then it will be touchy. Have you actually measured for this critical dimension? Interesting study though.

Hal
--
1977 Royale 101348,

1977 Royale 101586, Diesel powered,

1974 Eagle Bus 45',w/slideout

[Mike Sadlon]

To answer the transmission, most of the computers I am looking at have the ability to unlock or lock a Lockup convertor. It would just be a matter of
a relay to down shift the trans and the programing to make it work.

[Mike Sadlon]

Hal, can you get to facebook page. even if you hate facebook. I need to set up a GMC photo account, but haven't taken the time.
All my pictures are up there, on how the LS kit is going.

But the SBC/LS Motown block really has me going.

[Mike Sadlon]

The 427 hybrid short block gets my attention. not cheap, put all your low end torque thoughts go out the window.
There is no problem cubic inches and dollars does not solve.

[Mike Sadlon]

Hal
My 95 Buick Roadmaster wagon has a 2002 5.3 LS in it. What is it with us with old wagons?

[Mike Sadlon]

kerry pinkerton wrote on Thu, 20 April 2017 20:00
> Mike S wrote on Thu, 20 April 2017 18:29
> > ... It was great meeting you in Dothan.
>
>
> I remember you now Mike. (I cheated and looked at your FB photo) Aren't you the ex HP guy?


HP?

[Kerry Pinkerton]

Mike S wrote on Thu, 20 April 2017 18:29
> ... It was great meeting you in Dothan.


I remember you now Mike. (I cheated and looked at your FB photo) Aren't you the ex HP guy?

--
Kerry Pinkerton - North Alabama

77 Eleganza II, 403CI, Manny Brakes, 1 ton, tranny, lots of aluminum goodies.

http://www.bdub.net/pinkerton/

'03 Fleetwood Discovery 39L

[Johnny Bridges via Gmclist]

HP - instrument manufacturer that sells computers now and again.

--johnny
--
76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased

[gene Fisher]

So, are yum all saying,
A gmc will go 8'to 10 mph depending on if you tow ?

--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://gmcmotorhome.info/
Alternator Protection Cable
http://gmcmotorhome.info/APC.html

[Sigmund Frankenfelter]

Speaking as someone who has recently rebuilt my transmission, (relying on YouTube and other written guides) I do see a problem with a high horsepower
modification. For my tranny, I was able to find plates and seals. I even grabbed a Ragusa pan for the unit. The thing shifts great, stays cooler,
doesn't leak and I call the rebuild a success. But there was one part I was unable to get - the drive chain. I tried a dozen transmission shops, a
dealer and the rest of our usual sources. I know Manny has a few, but I don't blame him for keeping those for his rebuilds.

Straight to the point, I figure the drive chain could more easily stretch and fail in a high horsepower/torque environment. I already had the maximum
play allowable, but had to put the used chain back in because I could not get a new one. So I'm kind of babying it. Good shifts at 5-7 mph and 23 - 25
mph, but I keep thinking about that stretchy drive chain.

Sure, who wouldn't like fuel injection and variable valve timing and maybe even a computer controller ?? But I do think that the best new engine
would be one that comes matched with a modern transmission. I am pretty sure these 40 - 50 year old transmissions are going to start to go fast if we
mate them to much môre powerful engines.

[Chris Tyler]

First thing [which I think we can all agree on] whatever improvement in milage - if any- via any of the setups mentioned- will likely NEVER pay for
themselves even if you do all the labor yourself.

Couple of years back was working on a "science project"with my BIL re trans mods and swaps for the GMC. Items considered doable included lower 1st/2nd
gearsets, lock up converter, switch pitch converter conversion and some internal tweaks. His business has taken off to the point he can hardly keep up
with the HP builds while I was sidelined with complications from 2 hip surgeries so they havent been fully realized.

Regarding 425 torque capacity, his feeling is that the drive chain is the weak link but can be upgraded

Also looked at the 4WD case/blocked rear idea- its doable but would require extensive mods and cubic money

I am a huge fan of the LS engine series and think this can work...if you want to spend the money. An iron block LQ9 with a stroker crank will get you
around 400 cid fairly easily. Add small turbo[s] even to a 5.7 and you will have a torque monster. I know for an absolute fact you can make 556 #/ft
at 3500 on a bone stock LS1 at 10# of boost and still get 35 mpg hwy in a corvette

Im also a huge fan of turbos. Set up for low end boost vs HP {IE small housings and wastegates] you could hget by with a smaller engine under cruise
conditions


Another option would be the conventional SBC/383 stroker. I had one with twin turbos in a mid engine vega
Even a 350 single turbo works well for a tow rig

I understand Jim B was looking at a turboed Olds 350 a while back


For myself, Im content with the 455 I have for now, especially since I dont use the coach much lately. However, as i have mentioned before, at some
point I will probably ad 2 small turbos and a early model fuel injection system to it
--
76 Glenbrook

[Charles R. Botts]

Our CO-OP 454 motor with 3.42 differential produced 125% torque over stock at 65 mph measured on a Dyno. It is in a 10,000 pound 23’ GMC and we cross the southern continental divide at 65 mph.

[Johnny Bridges via Gmclist]

Well, I want someone to look at a wrecked Ram Promaster diesel and see if the driveline might transplant. The allowable GVW on them is in line with a
GMC. The option is Manny's upgrade. The idea of a Tonowanda Turd in my GMC is not gonna happen.

--johnny
--
76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased

[Mike Sadlon]

First, This isn't about mileage or even cost. Anything that goes round and round will wear out.
My GMC burns about 1 quart of oil every 500 miles, and I am OK with that vs. the cost of a rebuild.

Second, the last 455 casting was done sometime in the 70's. When I helped out at my buddies engine shop, about 50% of the engines that came in for a
simple rebuild, took some kind of major component. That's why the top shops are quoting $7500 for a rebuild. It is not customer friendly to say $5000
and to then come back and say you need another $1500 because your block won't take a rebuild. The rarer the more money.

Third. The LS would be a perfect motor, if it would bolt up with just an adaptor(that are out there cheap), a custom oil pan and front mount(easily
fabricated). You could sell those parts for around $500 and be OK making them. So a $500 kit, $2500 late model low mileage junk yard engine,$400 wire
harness and $300 computer tune and your running.

I will make a kit to bolt up the LS to the 425 transmission. But It needs custom front mount, rear mount, oil pan, trans pan, and an adaptor between
the differenial and the trans. I am looking at $1800 to $2000 for those parts. And to fit our coaches, you are going to have to add 3 inches to the
height of the step near the transmission to make it work. And it is getting real close to the hatch. it may even need to be raised a little to clear
the truck intake.

So what are the other choices?

To me there are 2 that make sense.

First the more expensive. World Product sells and engine called the LS hybrid. It is small block Chevy based bottom end, set up to take LS cylinder
heads. Again, it is not cheap. The first quotes on the short block exceed $5500! With a fresh set of heads and all the other component, It will
probably be near $10,000 for complete engine ready to drop in. But you will get easily 450 HP and 500 torque.

As always speed costs.

The other option is GM sells a motor they call HT383. Google it. It has almost the exact horsepower and torque of our stock 455s. The front mount and
pan prototypes will be done soon. you will have to raise the hatch, and I will let everyone know how much soon. Jegs has the motor for $4500. It has
a 2 year 50,000 mile warrantee. Add a Fitech fuel injection and you would have a great motor for our coaches. Keep in mind all your front accessories
need to be changed. But GM does sell a kit with everything you need, brand new, for about $1000.

How much is brand new worth vs. 40 year old everything!

[Hal StClair]

The WP Motown block is a whole different motor in comparison to the LS series'. They may use the LS heads but have the traditional SB lower end. The
deep skirt LS block still looks like a problem to me. The small block pan is only there to capture and store oil and is an easy uncomplicated piece
open to modification so thats a simple mod.
You'll probably have issues with the oil filter but a remote mount would be easy. Don't know how your fan will land in comparison to the 455 but a
modified or new shroud may be required. Power steering and A/C lines will probably need addressing too as well as alternator and sensor wiring but
nothing earth shattering. These are a fairly simple problems but would need to be addressed. The simpler the swap the more people that would attempt
it. I'm certainly not the one to 'dis' this project and love that you're taking it on.
The 383 has been around for a LONG time. I have a 364" stroker in the garage I've never run. But, the Olds blocks will certainly out live the Chevy's
as they were built using a higher nickel content block so, bottom line, 'you spend your money the way you feel best'. If you think gas is a better
direction than diesel, go for it. I'll be watching with great interest.

Hal
--
1977 Royale 101348,

1977 Royale 101586, Diesel powered,

1974 Eagle Bus 45',w/slideout

[Chris Tyler]

I think Hal is right regarding diesel as being the best for milage, reliability and durability.

While Ive have wanted a diesel to play with do some time dont know I want one in the GMC. How is the noise factor with that?

Of course, it would sound better with a little turbo whistle, kinda like the duece and a halfs in the army. [mechanic told me they put the turbos on
those to lesson the blck smoke emissions and they didnt really make any more power with them. Hmmmm....]

MikeS, as discussed on FB: The HT383 should work fine, may even fit under the stock hatch depending on the manifold you go with. I had a vega with the
mid engine, twin turbo 350/425. BIL has it now and will be reomving the engine to put in my Monza and a built 700R4, but we need to change oil pans. I
can send you some pics to give you an idea what to use. I THINK it would clear a 3.75 stroke but not sure

He is contemplating a big block for the car, if he goes that route the pan will be for sale.

The issue with the WP block and longer skirts could be a problem- It looked like the deeper skirts on the LS was going to be as well, but the double
tilt idea might get around it

THE LS hybrid is a great concept for HP use, but I dont think it really offers much for our application at the lower RPMs we need. I think the low end
airflow on hte Vortech type heads on the HT383 would be as good or better
--
76 Glenbrook

[Mike Sadlon]

I will let others play with the diesels. Manny is the only one who can work around the torque vs, 425 trans. I have heard they have sheared the torque
convertor bolts. If I have heard wrong someone let me know.

The HT383 would be right there on power. With some options on upgrades. If I needed a engine tomorrow, It is what I would do.

I speced the Hybrid with pistons to work with the stock truck heads. The CI increase to 427 would add all the low end torque we could ever need. And
should make a really nice torque curve.

I'm going to start with a pan that will clear the 4 inch stroke. That way all options could be on the table. From turboed 350 to 440 small block

[James Hupy]

The torque converter bolt issue is an operator caused one. About the same
time in production that GM went to METRIC wheels on trucks and HD 4 x 4
stuff, they also went to METRIC in their transmissions. Some of those
METRIC torque converters found their way into TM-425 aftermarket. They use
METRIC bolts on the torque converter. Due to inattentive technicians, or
inexperienced technicians, USS bolts left from OE torque converters found
their way into the assembly. They "kinda" fit for a couple of threads, and
then just lock up without clamping the flex plate to the torque converter.
Bad stuff happens quickly, here. I have fixed a couple of these in my shop,
and advised some owners over the phone with similar problems. The mismatch
is complicated by rebuilders painting their converters the wrong color, and
installers assuming that a converter is USS instead of METRIC because of
the color. Verify the converter by testing the bolts before assembly.

Jim Hupy
Salem, Or
78 GMC ROYALE 403

[Johnny Bridges via Gmclist]

The M-35s we had ("Deuce and a half" field grade truck) were about half turbo and half normally aspirated. The turbos outran the others and hauled
more weight... although that was above the listed capacity. And, the turbocharger screaming away right under the passenger side floorboard would give
you a headache after an hour or two at freeway speed. About the time I got Out, we started receiving trucks with Allison automatics in them. We
called them the 'Ladies' Deuce'.
The M-35 is about as indestructible road vehicle as you'll find.

--johnny
--
76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased

[Mark Sawyer]

Mike,

I'm going to preface my reply with this statement: I too love LS motors. I have an 89 Mazda RX7 that I swapped in an LS6 a few years back. I also
daily drive an 05 GTO, (LS2) and my wife daily drives a G8 (L76) that has 200K miles on it and counting. They're great motors. That being said, I
don't see any real advantage at this time in swapping one into my GMC. You can rebuild a 455 with all new parts except for the block and crank. Both
of those items are able to be inspected and deemed "Good" or "Not Good". There is no advantage to a brand new block over a good 40 year old block.
When my 455 needs a rebuild, I will rebuild the 455, and anticipate having no issue doing so for some years to come. (FWIW, I'm 41, and plan to have
our GMC for at least the next 25 years...) If 455s/455 parts become scarce, I would probably then switch to a Caddy engine. It is a true bolt in,
and you should be able to reliably get parts for them for a very long time, as Cadillacs have been, and most likely will continue to be collectible.

If I had the $ now, or if gas prices go through the roof, I would opt for a diesel. The 6.5 swap Manny and other such as Hal have worked out, looks
to be a great option. If the 6.5 is not refined enough for you, Cummins is planning to release a line of crate engines. The 5 liter Cummins V8 looks
like an awesome fit for the GMC, but I'm sure it will cost boatloads for a Cummins crate.

Also, if you go this route as opposed to the 6.5, you would be pioneering literally everything. Having done a few engine swaps in addition to the LS
motor in my RX7 over the years, I can tell you there is a lot to it. Lots of detail work in addition to the big things like getting it to fit. And
at least for me, to go through all that, there have to be some significant gains... And I don't see that with an LS over the 455.

For example, LS motors, if taken care of are easy 200K motors... -IF- they are pulling around a truck that weighs 5K, and sometimes tows a trailer.
GMC is 10-12K pounds, and has a pretty large frontal area to boot. I would guess they are more like 100-150K in motorhome service. 455 is similar...
Maybe a little less, but not enough to warrant the effort of putting an LS in my GMC. And a good LS rebuild is not much less than a good 455
rebuild. Say 5K for a decent LS rebuild. Yes you can do it cheaper. I can spend less rebuilding a 455 as well. But you'll get what you pay for
either way.

Now, if you absolutely have to have an LS in your motorhome, you want to start with a truck motor. The 2 crate engines you mention above are not
really for HD truck use... They're more light duty truck or muscle car. If I were to LS my GMC, I would at least go with a Gen IV, iron block LS
motor. The rectangle port heads (often called L92 or LS3 heads) are damn near magic when it comes to flow, torque production, etc. I would probably
opt for the 6.2 so look for an L92 or L99 engine. Even better would be the Gen V L86. These add direct injection, variable speed oil pump, etc....
Lots of little tweaks to increase efficiency. This is arguably (arguable with Ford and Mopar guys ;) the most efficient gasoline engine available for
motorhome use. And even with all that, it's only marginally more efficient than a 455 when pulling 12K pounds.

Now, for your swap, you mention physically bolting on the trans, and modifying the oil pan and engine mounts, modifying the interior step and maybe
raising the hatch height. When forcing an engine into a vehicle it was not designed for, that's only the beginning:

Finding Radiator/heater hoses that work with this swap
Adapting the gauges, buying new gauges to work with the LS
Adapting the LS wiring harness to "interface" the LS brain with the GMC. ignition switch, etc.
Buy new ECU ($$$$), or modify truck ECU. Disable anti theft key, (VATS) other ECU changes to allow the engine to run without the rest of the truck it
came in
Are you going to run a catalytic converter? If yes, modify GMC to run cat. If not, reflash ECU to remove cat emissions system from diagnostics.
You going to run stock manifolds or go with headers? Either way, you need to modify the exhaust on GMC
No evaporative emissions system on GMC. Modify GMC to add it or reflash ecu to remove it from diagnostics
Modify GMC fuel system. LS motors are high pressure, returnless fuel systems stock.
What are you going to do with engine oil cooling?
Gen IV and up LS motors use an electronic throttle, you'll need to figure that out, though there are options (Electronic gas pedal or switch to older
ECU and reluctor wheel with mechanical tbody)
How do you run the mechanical TH425 on an engine designed for a computer controlled transmission? Again, there are options, but it needs to be
considered
Modern truck is going to generally have a higher amp alternator (150 amp or so?). You'll need to verify your GMC can handle that current and modify
accordingly
AC system will need custom hoses made. LS AC runs through ecu, so you'll need to modify GMC AC system with necessary sensors.
I love my cruise control on long trips. I consider it a must. Need to figure that out.
Will need some way to interface with the ECU... OBDII connector?
Hal mentioned cooling fan, shroud modification, etc above.

So after all that, you end up with a GMC with an LS motor. You get 8-10 MPG, with an engine that lasts ~100K miles, has around 400hp and tq, and
costs $5K to rebuild.







--
Mark S. '73 Painted Desert,
Manny 1 Ton Front End,
Howell Injection,
Leigh Harrison 4bag and Rear Brakes,
Fort Worth, TX

[Ken Henderson]

Happy as I am with my Cad500, and being too old to launch into another
"upgrade", I'm not about to get into this discussion. But, I recently had
a surprise that influences the longevity of the 455: NEW crankshafts are
now available, removing them as an unobtainium part! One source:

https://www.summitracing.com/parts/esp-104554260/overview/make/oldsmobile

Ken H.

On Mon, Apr 24, 2017 at 6:40 PM, Mark Sawyer <mark.s...@gmail.com>
wrote:

> ​...

> You can rebuild a 455 with all new parts except for the block and crank.

> ​..

[Mike Sadlon]

Since most of you out there do not know me, maybe a little background is in order.

I am 55. I learned to weld and fabricate at 13, Worked on a farm as a youth(boy the things you learn there). Had my first street rod at 15. Built my
first Rod at 16. Had 3 periods a day of machine shop 1 year. Rebuilt my first motor at 17. Spent 2 1/2 years at college studying mechanical
engineering. Left college to work for an ARCA race team. Built a motor that qualified at Daytona ACRA race 7th. 1981 ACRA national champions, I was
the only full time paid guy on the team. Multiple local short track championships. Been boat racing for over 30 years. Tunnel, offshore, hydroplanes,
P1, and lots of lake racers.

Engine transplant history
1995 Buick Roadmaster wagon-2001 5.3 ls
1972 Chevy Greenbrier(chevelle) wagon-1995 LT1
1972 Chevy El Camino-1992 throttle body 350
Friends 1967 Toyota LandCruiser Tuned port 383
Friends Jeep CJ 5 383 Holley Projection
Jeep CJ 7 Glass tub Chevy 4.3 V6
1930 Model A ford Pickup- 4 wheel drive 4 inches off the ground. Built in 192 with 1987 1 piece pan 355 ci 6 inch Rod Motor
I had my own Semi repair garage for 3 years. We were a Consolidated Freight primary vendor.

I worked on my first GMC in 1984, We had a doctor whose coach we maintained for 5 years. That's when I feel in love.

First meet Alex Sirum in 1985, when I spent 2 winters working in the marine business in Okeechobee.

I was one of the first 150 people hired at Steel Dynamics. We built a steel mill in a corn field. Worked 10 years as a millwright. One of the most
technical/mechanical jobs you can have.

I have a little experience.

Again, this project comes from a conversation with Jim Bounds and backed up with Jeff Sirum.

We are going to need another motor if these coaches are to last the next 40 years. When I built the first street rod in 1977, I was not going to just
rebuild the model a engine. I could have. And people are still rebuilding Model As, But engines options had gotten much better in the 46 years since
the original.

If I needed a new motor in my Coach, has motor technology improved in the last 43 years, YES

Would I do something right now, I don't know.

Jim would love to have a new crate engine to put in his customers coaches. To quote Jim, "If I had a good crate engine, I would never rebuild another
455."

He has done other conversions, most of us know that. It takes a lot of time to develop a new package. He has employees and customers and obligations.
When we talked, he said he would be interested in buying kits if they could be made.

I have a great relationship with Jeff Sirum. I retired at 55, but I wanted a small shop to help out retirement money. I am already doing all Jeff's
fiberglass parts. And we are making new molds for parts that are not currently available. We have the Dash Cover, New improved molds for interior cab
sides. Next is a new cab interior cap mold. And after that we are going to be able to keep the stock dash with a new "birdcage" part.

The "small block" pan and front mount will be easy. Like I said above, If I needed a motor replacement, I would put in the HT383. On longevity.
Everything that spins has a life span, any bearing engineer will tell you that. reduce the load, like reduce the vibration or amount of out-of-balance
and you will increase life. The new motors go 200,000 miles because of technology, they only have to go around 1/2 as much. Look at the gearing in you
truck. they can go down the road at 1500 rpm.
Half what our coaches do.

Do I believe long engine life is possible with good maintenance, Sure Do. you can cook down a brand new motor with just 1 small coolant leak. Ben
there done that. More engines fail from poor maintenance than just wear out.

Would I be comfortable with a 100,000 mile motor, Heck Yeah, if it never gave me any problems. How many miles are we averaging a year in our coaches?
I am averaging 7,000 miles. I think that is on the high side of average. So at the end of the next 14 years, I need to replace the power plant, I will
do it with the newest Mr. Fusion.

I agree, the LS conversion is not easy. It's why only one person I can find bolted one up. And he had to mill down the block. Not really a bolt in.

I have had interest in the LS from outside the GMC community. I will build the pieces. They won't be cheap because there are a lot of them. And will
it fit our coaches well? NO. Would they work great? Probably. Will somebody want one? I don't know.
I kind of hope, "If I build it, they will come."

Once I build the hard parts, if someone wants to partner up on the first LS build, I will do it. We will figure out the parts needed and put it out to
the world. Anything can be done with enough time and money.

Mike

[Kerry Pinkerton]

Mike, it sounds like if anyone has the skills and connections to put a modern engine in our coaches, you're him. And someone has to be first so go
for it. If nothing else it will work but not be economically viable. You won't know until you know.

And worse case, you'll have a coach with something no one else has...kind of like my electric disappearing table. :d. It's not economically viable
but it's certainly unique.

--
Kerry Pinkerton - North Alabama

77 Eleganza II, 403CI, Manny Brakes, 1 ton, tranny, lots of aluminum goodies.

http://www.bdub.net/pinkerton/

'03 Fleetwood Discovery 39L

[Mark Sawyer]

Mike, I'm sorry if I came off as saying you were not capable of doing the swap. That was not my intention. My point in listing all that stuff out
was to illustrate the point that engine swaps are a lot of work... And that the 455 and Cad 500 really are good motors for our application. You are
100% right, at some point we will NEED a new engine option... I also agree with you that the LS motor is the best gas engine out there right now for
the job. But good god, it's a lot of work to get it in there and working, then add all the ancillaries as well...

But you are also correct in saying that the more options we have, the better off we will all be. I'll tell you, if I were going to do an LS swap on
the GMC, and I needed to modify the interior anyway, I would probably look the possibility of using a 4L80 to get the extra gear and lockup
converter.... I believe Hal's diesel setup uses a 4L80 or similar, and some sort of transfer case to get power back to the front...

Hal, could you maybe describe how your setup works?

--
Mark S. '73 Painted Desert,
Manny 1 Ton Front End,
Howell Injection,
Leigh Harrison 4bag and Rear Brakes,
Fort Worth, TX

[Dolph Santorine]

I understand where everyone is coming from regarding the engine, but I think what will kill the GMC Motorhome in the end is transmission parts availability.

I just completed a rebuild on a 1922 Overland. Pistons, rings, gaskets - all available, as they will likely be for the 455 or the 500 in half a century.

Transmission parts, not so much.

Dolph

DE AD0LF

Wheeling, West Virginia

1977 26’ ex-PalmBeach
1-Ton, Sullybilt Bags, Reaction Arms, 3.70 LSD, Manny Transmission, EV-6010

“The Aluminum and Fiberglass Mistress"

[Johnny Bridges via Gmclist]

I took a look at the ProMaster diesel, and I don't think it'll fly. It looks to require serious surgery in the front of the coach. Plus, the one I
saw fits the MV four cylinder, not the V6. I got the impression the V6 only appears on the home market in bigger trucks, though I might be mistaken
there. At any event, it isn't going to be like stuffing Mustang running gear in a Ranger.

--johnny
--
76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased

[A.]

TR 1 wrote on Tue, 25 April 2017 09:33

> Mike, I'm sorry if I came off as saying you were not capable of doing the swap. That was not my intention. My point in listing all that stuff
> out was to illustrate the point that engine swaps are a lot of work... And that the 455 and Cad 500 really are good motors for our application. You
> are 100% right, at some point we will NEED a new engine option... I also agree with you that the LS motor is the best gas engine out there right
> now for the job. But good god, it's a lot of work to get it in there and working, then add all the ancillaries as well...
>
> But you are also correct in saying that the more options we have, the better off we will all be. I'll tell you, if I were going to do an LS swap
> on the GMC, and I needed to modify the interior anyway, I would probably look the possibility of using a 4L80 to get the extra gear and lockup
> converter.... I believe Hal's diesel setup uses a 4L80 or similar, and some sort of transfer case to get power back to the front...
>
> Hal, could you maybe describe how your setup works?

IIRC, Hal used the engine/transmission/transfer case because that is what he had on hand (4-speed).

A similar setup with 5 or 6 gear tranny would be better. More gears in the tranny is always better. Continuously variable is ideal, but not many sizes
have ever been made, and nothing big enough to drag a GMC class A.

If anyone ever decides to make a drop-in front-wheel-drive engine/tranny combo (with other than the THM-425) 6 speeds should be the goal.
--
73 23' Sequoia 4 Sale
73 23' CanyonLands Parts Unit 4 Sale
Upper Alabama
"Every day I become more convinced that I am the only person left on the planet that recognizes nonsense for what it is."

[Kerry Pinkerton]

Since the title of this thread is new engines and not just LS conversions, let me throw this out.

Has anyone looked at the Caddy Northstar. The supercharged version had gobs of horsepower and torque and bolted up to a modern FWD overdrive tranny.
I don't know anything about the rear end ratio but the performance versions of the Caddy could really scoot so I'm thinking multiple ratios were
available.

--
Kerry Pinkerton - North Alabama

77 Eleganza II, 403CI, Manny Brakes, 1 ton, tranny, lots of aluminum goodies.

http://www.bdub.net/pinkerton/

'03 Fleetwood Discovery 39L

[A.]

jknezek wrote on Tue, 25 April 2017 12:49
> ...my kids have turned my memory for anything besides where they need to be when into mush...
Blame your kids if you want, but that has nothing to do with it. Wait until you hit 49 or 59, or ... what was I saying?

--
73 23' Sequoia 4 Sale
73 23' CanyonLands Parts Unit 4 Sale
Upper Alabama
"Every day I become more convinced that I am the only person left on the planet that recognizes nonsense for what it is."

[Jeremy]

kerry pinkerton wrote on Tue, 25 April 2017 13:24

> Since the title of this thread is new engines and not just LS conversions, let me throw this out.
>
> Has anyone looked at the Caddy Northstar. The supercharged version had gobs of horsepower and torque and bolted up to a modern FWD overdrive
> tranny. I don't know anything about the rear end ratio but the performance versions of the Caddy could really scoot so I'm thinking multiple ratios
> were available.

I'm pretty sure someone poured cubic dollars into this about the time I joined, close to a decade ago. I think it eventually got abandoned? Don't
quote me on that. I'm turning 39, not 29, so anymore, so my kids have turned my memory for anything besides where they need to be when into mush...
--
Thanks,
Jeremy Knezek
1976 Glenbrook
Birmingham, AL

[Ken Henderson]

'Way, 'way back, Pete Pappas bought a Northstar front end and spent many
hours contemplating its possibilities for the GMC. I sat with him through
some of that. Neither of us could visualize any way to meld the two;
certainly not without a new front frame clip.

He abandoned the idea and instead RV'd an RTS bus. Seemed think that was
easier, even if it did take him a couple of years. :-)

Ken H.


On Tue, Apr 25, 2017 at 1:24 PM, Kerry Pinkerton <Pinke...@mchsi.com>
wrote:

> Since the title of this thread is new engines and not just LS conversions,
> let me throw this out.
>
> Has anyone looked at the Caddy Northstar. The supercharged version had
> gobs of horsepower and torque and bolted up to a modern FWD overdrive
> tranny.
> I don't know anything about the rear end ratio but the performance
> versions of the Caddy could really scoot so I'm thinking multiple ratios
> were
> available.
> --

[Mark Sawyer]

Northstars had headbolt issues, no? If you're looking at transverse mount, the LS4 in the Grand Prix GXP would be another option...


But really, we should probably all be jumping on the Manny diesel kit. If we could get some volume going, that really would be the best option.

--
Mark S. '73 Painted Desert,
Manny 1 Ton Front End,
Howell Injection,
Leigh Harrison 4bag and Rear Brakes,
Fort Worth, TX

[Peer Oliver Schmidt]

I'll repeat what I wrote on FB: I'll wait for in-wheel e-motors come
available like the once done for the rear wheels of a Honda in
midwestern university. Couple that with a smaller engine up front, and
you are golden, imho.

Diesel sounded good a while ago, but with changes in laws in Europe,
Diesel will not be so good anymore, due to city-drive restrictions. My
0,02EUR

--
Best regards

Peer Oliver Schmidt
the internet company
PGP Key ID: 0x83E1C2EA

[RC Jordan]

>diesel

After hearing the noise produced by the coach with Manny's diesel, I'm far less interested in the conversion.
--
77 Royale Coachmen Side Dry Bath
76 Birchaven Coachmen Side Wet Bath
76 Eleganza
Elizabeth City, NC

[James Hupy]

Noise from diesel engines is much less of a problem as the years go by. I
put a fancy sound system in my coach complete with tri-axial speakers and a
cd player. Haven't turned it on in years. Installed a flat screen tv. Took
it out. Never turned it on, either. Nothing but DRIVEL on it. Much rather
enjoy my panoramic view and visiting with my GMC friends. Just how we roll.
But, I am an engine guy, I want to hear it run. My sister has a different
philosophy, when her engine makes unusual noises, she turns up the volume
control. Different strokes.
But, significant noise reduction is possible with some excellent
damping materials available today. I covered my ONAN compartment with
DYNAMAT, and followed it with pet proof carpet padding. You can still hear
it, but much more tolerable. If you really value quiet operation vs fuel
economy, use a Ford V-10 Triton. Very quiet at 6 miles per gallon. A good
diesel will triple that mileage, and outlast two Triton's.

Jim Hupy
Salem, Or
78 GMC ROYALE 403

[Johnny Bridges via Gmclist]

A run around the block with Bounds was to a degree noisy.... but I think the bulk of the noise could be shut up with some thought and more sound
deadening. As to mileage, I don't think 18 is gonna happen in a GMC until you transplant a different transmission. If then. However, get 12 - 14
and your fuel costs are the same as the gas ones or a bit less.
Putting a different gasoline engine in a GMC using the THM-425 (with the exception of the Cadillac) seems to me an exercise in 'can I do it'. More
power to those who do. But it does nothing for the coach in my uses.

--johnny
--
76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased

[James Hupy]

I once put a 354 Chrysler Hemi in a 1934 Ford 5 window. Along with B&M
Hydrostik. 8 Stromberg 2 barrel carbs on a Homemade "log" manifold. MERCURY
STATION WAGON rear end with 3:90 to 1 rear end gears. It fit with the aid
of a Sawzall and oxy/acetylene torches. Hell of a lot of work, for a
brutal, Ill handling beast of a bump steering, front end heavy, monster.
Went like jet stink in a straight line. Got 3 or 4 miles per gallon.
Sounded really "bad" with all those carbs and the Chet Herbert Roller Cam.
Today, wouldn't have it on a bet. Funny how stuff changes.

Jim Hupy
Salem, Or
78 GMC ROYALE 403

On Apr 27, 2017 9:23 AM, "Johnny Bridges via Gmclist" <

[Johnny Bridges via Gmclist]

Not counting Hal's, which are a cut above, the best two transplants I've seen at least for use, were a Sideoiler a friend put in a '56 Crown Victoria
and my little Ranger. Both added some steam without screwing up the original to any great degree. The Cadillac engine in our coaches is the same
sort of improvement. And if you want 'silly' you can give it the JimK treatment - punch it out to 540 CID and hang a pair of turbos on.

[Kerry Pinkerton]

Johnny Bridges wrote on Thu, 27 April 2017 11:22
> ...Putting a different gasoline engine in a GMC using the THM-425 (with the exception of the Cadillac) seems to me an exercise in 'can I do it'.

> More power to those who do. But it does nothing for the coach in my uses.
>
> --johnny

I'd agree and I'm firmly in the 'just because I can camp...' FIRMLY! A different engine with the same tranny just isn't feasible as long as we can
still get parts and cores for the Olds/Caddys.

I have a fresh 500 sitting at John Beavers shop waiting run-in. It's going in the car hauler. If I could find a good deal on a modern 5 speed OD
tranny and transfer case I'd see if I could adapt it to the 1 ton hubs using a generic GM differential similar to what Hal StClair did. I think it
would be doable and we'd have a jillion rear end ratios available for cheap. There are no shortages of Caddy cores. I'd consider doing this...'just
because I can...':) Of course if I can adapt a Caddy to a new tranny, adapting a LS motor would be a snap. Plus I don't have to worry about steps or
hatches but I'd try to work within those constraints just because it would be good to know.

I'm also planning on installing a Chevy 1 ton front end but will make new control arm mounts and use the stock control arms.

I'm going to pull the subframe from the parts coach that will become the car hauler and do all this fab work on my welding table so I can jig
everything up.

I wish I lived near to some of you guys. This would be a lot more fun working with someone.

Anyone got a 5 speed auto and transfer case they want to swap for a good Honda EV6010?

--
Kerry Pinkerton - North Alabama

77 Eleganza II, 403CI, Manny Brakes, 1 ton, tranny, lots of aluminum goodies.

http://www.bdub.net/pinkerton/

'03 Fleetwood Discovery 39L

[rich...@comcast.net]

I find these replacement engine ideas very interesting, but the nearer term problem for all of us is the transmission. What can be done to come up with a replacement? We are quickly running out of rebuild kits.

----- Original Message -----

From: "Mike Sadlon" <Captn...@gmail.com>
To: gmc...@list.gmcnet.org
Sent: Sunday, April 23, 2017 7:29:14 AM
Subject: Re: [GMCnet] new engines for the GMCs

First, This isn't about mileage or even cost. Anything that goes round and round will wear out.
My GMC burns about 1 quart of oil every 500 miles, and I am OK with that vs. the cost of a rebuild.

Second, the last 455 casting was done sometime in the 70's. When I helped out at my buddies engine shop, about 50% of the engines that came in for a
simple rebuild, took some kind of major component. That's why the top shops are quoting $7500 for a rebuild. It is not customer friendly to say $5000
and to then come back and say you need another $1500 because your block won't take a rebuild. The rarer the more money.

Third. The LS would be a perfect motor, if it would bolt up with just an adaptor(that are out there cheap), a custom oil pan and front mount(easily
fabricated). You could sell those parts for around $500 and be OK making them. So a $500 kit, $2500 late model low mileage junk yard engine,$400 wire
harness and $300 computer tune and your running.

I will make a kit to bolt up the LS to the 425 transmission. But It needs custom front mount, rear mount, oil pan, trans pan, and an adaptor between
the differenial and the trans. I am looking at $1800 to $2000 for those parts. And to fit our coaches, you are going to have to add 3 inches to the
height of the step near the transmission to make it work. And it is getting real close to the hatch. it may even need to be raised a little to clear
the truck intake.

So what are the other choices?

To me there are 2 that make sense.

First the more expensive. World Product sells and engine called the LS hybrid. It is small block Chevy based bottom end, set up to take LS cylinder
heads. Again, it is not cheap. The first quotes on the short block exceed $5500! With a fresh set of heads and all the other component, It will
probably be near $10,000 for complete engine ready to drop in. But you will get easily 450 HP and 500 torque.

As always speed costs.

The other option is GM sells a motor they call HT383. Google it. It has almost the exact horsepower and torque of our stock 455s. The front mount and
pan prototypes will be done soon. you will have to raise the hatch, and I will let everyone know how much soon. Jegs has the motor for $4500. It has
a 2 year 50,000 mile warrantee. Add a Fitech fuel injection and you would have a great motor for our coaches. Keep in mind all your front accessories
need to be changed. But GM does sell a kit with everything you need, brand new, for about $1000.

How much is brand new worth vs. 40 year old everything!

[Hal StClair]

TR 1 wrote on Tue, 25 April 2017 08:33

> Mike, I'm sorry if I came off as saying you were not capable of doing the swap. That was not my intention. My point in listing all that stuff
> out was to illustrate the point that engine swaps are a lot of work... And that the 455 and Cad 500 really are good motors for our application. You
> are 100% right, at some point we will NEED a new engine option... I also agree with you that the LS motor is the best gas engine out there right
> now for the job. But good god, it's a lot of work to get it in there and working, then add all the ancillaries as well...
>
> But you are also correct in saying that the more options we have, the better off we will all be. I'll tell you, if I were going to do an LS swap
> on the GMC, and I needed to modify the interior anyway, I would probably look the possibility of using a 4L80 to get the extra gear and lockup
> converter.... I believe Hal's diesel setup uses a 4L80 or similar, and some sort of transfer case to get power back to the front...
>
> Hal, could you maybe describe how your setup works?

Been out of town for a few days, sorry.
I used a 4l80e behind the H1 Hummer 6.5 with B/W transfer case I located from Revcon MH. Although the transfer case is all but impossible to locate
today, one could use a NP205 TC which are easy to find and adaptors are readily available. I ran forward to a late model 9.25" AAM differential with
custom built equal length half shafts. These front diff's are available from 2011 up 1 ton Chevy/GMC trucks. Ratios are somewhat limited with 3.73 the
fastest offered from GM although a 3.42 was offered by AAM which is what I'm running now.
6.5's were never available with more than 4 speeds (auto's that is) as far as I know so any 6,8,or 10 speeds would have to be specially programmed and
built to handle the diesels needs. A 4l80e can be modified to have 5 or 6 speeds but it's an expensive process which requires internal gear ratio
changes to fully exploit the gear splits. A stand alone ECU would be required and you would loose the engine PCM's interface with the transmission
which would probably cause drivability issues. The 4 speed with the locking convertor seems to work very well and with the diesels high torque at
modest rpm's requires very limited downshifting.
Hal
--
1977 Royale 101348,

1977 Royale 101586, Diesel powered,

1974 Eagle Bus 45',w/slideout

[Kerry Pinkerton]

Check your PMs Hal

--
Kerry Pinkerton - North Alabama

77 Eleganza II, 403CI, Manny Brakes, 1 ton, tranny, lots of aluminum goodies.

http://www.bdub.net/pinkerton/

'03 Fleetwood Discovery 39L

[Mark Sawyer]

Hal StClair wrote on Sat, 29 April 2017 01:31

> one could use a NP205 TC which are easy to find and adaptors are readily available.

> Hal


NP205 is an interesting idea, Hal... And I think I'd like the idea of having a low range available if I needed the torque....

--
Mark S. '73 Painted Desert,
Manny 1 Ton Front End,
Howell Injection,
Leigh Harrison 4bag and Rear Brakes,
Fort Worth, TX