I have a 88 Trans Am GTA with a 305, and I got a 350 and crank from a guy from work. Im just into the phase of making a list of parts, and choices of what to do. I wanted to keep my top end the same other than fuel rail, injectors, and TB. My friend told me he will give me his LS1 head if pay half for his other once. He also told me I should bore over 30, I just want some input in what you think will work best or if thier is another way to go.

 

first,do a search, you'll find a lot of stuff.second, you can't interchange the LS1 heads with a gen 1 or gen 2 motor. it just doesn't work/fit/mount. what kind of shape is the new motor in? what did it come out of? what top end are you running? TPI? TBI? we need to know.

 

My top end is TPI, the block is a 4 bolt main. the block is in good shape it has been hot tubed, magnaflux, but Im still going to do it again just to make sure. Im not sure what the motor came out of how can I check.

 

if the top end is TPI you won't get 400hp out of a stock setup ever. You'd have to swap to an aftermarket FI setup of your choice, miniram, stealth ram, etc or to a carb setup. The tpi setup just can't flow enough air to support that kind of horsepower N/A.