I have a quick question and i didnt know how to word it right to get a good search so here it is. When swapping in an engine, does it really matter if it is from 80-85 or 86-90? I am speaking in V8 terms. Also do i have to change anything under the hood to acomodate an 86-90 engine in an 85 trans am? I have been reading jegs and summit and they always separate these two sets of years. thanks and sorry for the dumb question.

 

simple answer:

no.

the only real difference to pay close attention to is to make sure your flywheel and starter match up, and that you have a crank and heads to fit the block. meaning, you understand that using 86-up heads means modifying an earlier intakes center bolt holes, or buying a new intake to fit the heads. but the blocks mount the same way in the engine bay, and bolt to trannies the same way, and can use the same gaskets and bearings and cams and stuff.

 

You will need a different flywheel or flexplate. A 2 piece RMS flywheel can't be used on a 1 piece RMS crank and vice versa.