I am looking for a shop in the Central/Mid Michigan area that has a good rep with rebuilding GM posi rearends. I have a 10 bolt unit out of an early 70's Nova I need gone through.
I am not sure where you are located or how far you are willing to travel but DTS usually does good work: http://www.drivetrainspecialists.com/
I third DTS. They have a good reputation in the Metro Detroit area. Dad used them for the new rear in his Olds. I plan on having them go thru Big Olds's rear in the spring to try and figure out why I go thru passenger side rear wheel bearings every 20,000 miles or so.
Sounds like they are the guys to see. I am about 2.5-3 hrs north of them. I was hoping there would be somebody in the Saginaw area who was reputable as thats only an hour away. It's probably worth the drive to have the job done right though for sure.