First off, I think you're asking about 9004 vs. 9007, because these are
two bulb designs which on first glance look very similar. 9006 doesn't
look anything like 9004.
Secondly, no, 9007 is NOT interchangeable at all with 9004. Different
filament positions, different wattages, different base keying and
different terminal pinout. You could hack the bulb or the lamp to make it
fit, and it still wouldn't work right.
http://vrx.net/dsl/tsb/9004_9007.pdf
DS