thinking of doing the swap input wanted

Is there any differance in the blocks? Is one stronger then the other? I am going to shoot for 550hp and 500 ft lbs. The car runs mid 11s and I don't want to slow down but gain driveability. Has anyone used a big stuff 3 engine managment system? Which accessories hit the frame? I need an alt and thats about it, I would prefur to mount it low as it makes for a nicer look under the hood in my oppinion. Sorry for the questions?

Trevor