Not that much for trucks. You will have to buy or fabricate new motor mounts. Speed and performance sells adapter plates that allow you to use your stock mounting brackets (www.hotrodlane.cc) They also have the other resources like wiring harness, etc.

Performance will be no comparison between the two. Farmtruc is running 13s with a fairly stock LS1. There is no reason not to do the swap. Others here have done it and are willing to help.

Good luck!