Very easy swap. If the bolts in the lower control arms aren't frozen in place you can do the whole thing in about 4 hours.
I'm assuming that you want to add the posi to the existing rearend. The swap isn't too bad. Car should have a 7.5 rear. The posi can be sourced from either a Camaro or S-series truck. Not too bad of a swap, I'd budget a weekend to do this. If you got lucky and found a Regal Rearend, then 4 hrs is definately possible. Make sure to check all of the brake lines & hardware if your going this route. I did my GS in about 3 hours on a work nite. Jim 1969 GS California 455/4-spd/12 bolt 1982 Turbo Regal 454/TH400 "For Sale"