ok so theres a chance i might buy an 87 ROC with a 305 TPI in it now that comes with a 400 sm block. im not sure if the block is bare or assembeled yet but i was wondering if the TPI fuel injection system, water pump, ect all those accessories that bolt on the engine would be able to go from the current 305 and onto the 400?

 

the tpi setup will switch over, although i dont reccomend it...
you wouldnt want to use the heads or anything off the 305..
the water pump would work, but only if you keep the serpentine belt setup on it... i think most everything will swap over tho, but only if it;s done right...

 

Yes, definatly DO NOT put the 305 heads on. You would be shooting yourself in the foot. 305 heads are worthless as far as airlow goes, well they are pretty much worthless alltogether.

 

i'm running a 406 in my 87 Iroc. I'm running vortec heads and they flow great and are relitively cheap.

You will have to buy new injectors and get a custom chip be prepared for a large budget.