350 heads on a 305 really won't do anything I think 305-HO heads would probably be better then 350 but that really not worth doing unless u just have them sitting around or something, I'm pretty sure to swap that all u need are the motor mount plates that they sell for like $65 for the price their not even worth making them, and depending on weather your going fuel injection or carburation their still is going to be a lot of work cause yours is only the 2.2L, if your truck was a 4.3 everything bolts right up to the V8's, Their is so many things on the internet about swaping V8's in these trucks just do your research cause I gaurantee u someone has already tried it on an S10.......