I was just in J'ville today, doggone place is growing up. I live about an hour south in Wilmington.
As far as engine install and tuning, it depends on how far you want to go--if you don't want to leave J'ville--eh about the only place i would suggest is Majestic motorsports, although they are not a buick shop and prolly have very little experience with them, they could do it.
The best suggestion for you is Big Wood racing, they are about 1 1/2 hrs. away from you up I-40. Obviously they are a sponsor/owner of this board and they can handle anything you need done.
If neither of those work out for you, i have a couple more suggestions, but i would start with Big Wood.
Geoff
P.S.--anymore info on the engine install, stock motor, tranny already in the car, motor all assembled?--stuff like that.