I have an 86 iroc with 2.73 non posi, 700r4 and 305 high output with tpi out of a 87 trans am (head gasket blew on the original 305). 305 is only in there temporary while I finish the body work and interior The car only has 80k on it and I am trying to decide on the motor. I want to start my build from the rear end to the motor. I will be swapping the gears to either 3.73 or 4.11 posi pretty soon but cant decide on the motor. I can either get a gm 350 crate which goes for under 2k with 100k warranty and produces 290hp 300ft.tq, with this set up I would go with a brand new performance 700r4, keep the tpi for the motor and possibly supercharge it later on. On another hand I could go with an ls1/T6 swap but I believe this would be a much more expensive and less practicle way. Far more expensive and I would have to go with a used motor. I believe engine/trans combo goes for 6k+++++ My main goal is to get the most hp for the dollar but I want to keep on the streets. What do you all think?

 

I think you need to decide if you want to keep it simple with a Gen I SBC, or go LS1.

LS1 certainly is the better street performance platform. The 290 horse crate is a gross flywheel rating, poor heads, lame compression, standard (weak) components, while the least of the LS1's will put out 305 horse net flywheel, are made from "good" stuff, and respond well to modifications.

 

Do the LS1 swap. Find a truck 5.3 or 6.0 if the LS1 is too expensive.