There are several options. If you are talking about rebuilding the shortblock (and heads?), there is a real good buick-related mechanic near by in New Albany - Jeff Hickernel of Hickernell Engine. 855-2290, good, but not cheap.
You could also send it down to Lonnie Diers of Extreme Automatics in Cincinnati he has some contacts that can get the work done by a few good machinists in his area.