it is easy to swap over to a Chevy- the frame and engine mounts can be taken out of pretty much any Chevy powered car and truck built from 73-99.
you'll need to move some wiring around- but that's easy- and the fuel pump is on the other side of the motor compared to a Buick, but that's what hose was made for. you'll may need different power steering lines.
if you have an overdrive trans, then it should bolt right up to the Chevy. if not, then find a short shaft TH350 and bolt it right in.