Many posts on this, use the Search. Need special motor mounts, different transmission, driveshaft, maybe a different rear end, maybe an aluminum radiator, stiffer torsion bars if a street driver. Headers often need a cutout in the fender wells. If not, the exhaust is choked so much the BB doesn't make much more power than a SB. The result is hard to handle on the street and most people do it to make a drag racing only car.