80s frame, 72 body...

[72chevy327]

Hey, What mods are needed to fit a 72 box/body on a 85ish 4x4 frame? I have heard a 3" body lift to clear the shape at the back of the cab. cut the frame to a short box wheelbase because the 73+ ones have a bigger wheelbase, and move the core support brackets how much and witch way i do not know??? is this the only mods i will half to do? i am looking for a total of 6 inches of lift. Also what should i do with my steering system. Thanks!