I have decided that I am putting a Pontiac engine into my 82 Trans Am (the way they should have come from the factory). I have seen a couple guys posts that have done big block conversions on firbirds and camaros. I am mainly looking now for a couple answers currently. I am either going to use a 400, 455, or possibly a 400 with a kit from Jim Buttler Performance that will make the 400 into a 461-467 depending on how much I have to bore it. With all this power will I have problems with my M21 4 speed? Would a t56 5 speed be any better? How heavy of a rear end will I need 12 bolt (what modifications?)? Will a factory drive shaft be ok? Where did everyone get coils to hold the front end up? Also what power should I expect from each of the combos roughly (400, 455, or 400 stroker) not to set on any specifics for cam etc. but all in all will the 455 be alot more power than the 400. Thanks in advance.

 

a muncie M-21 will be more the fine for that pontiac, the driveshaft should be allright, the axle probley wont handle it, and the only way you can go is aftermarket there, so eather build the hell out of the 7.5 you have now (if it has one) or swap out the axle for a aftermarket one. also the 400 can make just as much or more power the the 455, also the 400 pontiac is MUCH easyer to find and cheaper to build then the 455, the 400 to the pontiac is the 350 to the chevy and the 455 is the 454 to chevy. (cheap and avilible parts wise) talk to bulter more about it, he's the master in pontiac stuff.