I hope you mean a 4.3L V6, and not a Ford 4.6 V8.

I'd definitely go with the V6, the 2.2 is so useless IMO. Underpowered FTL.

I'm sure you'd get more accurate responses as far as putting the engine in though, if this was in the GM Tech section. To the best of my knowledge, I think you could get away w/ the stock tranny, they might have used the same one for both engines. Not sure though, so don't hold me to my word.