If I was going to do it, the LS2 would be coming from a running vehicle that I own. This way, I know that I have all of the components needed for a successful swap. Mainly the full harness, gauge pack and any oddball sensors, etc. It should be plug & play, electrically.
there's a guy named dana @ LT1 wiring.com he mite be able 2 help u out with graphin your wiring harness 2 da LS2 engine and give you info on parts & installin da ls2 in a b-body. "google lt1wiring" its in eerie pennslyvania GOOD LUCK!