Paul, Where in eastern MA are you? I'm in Taunton and know of a couple reputable shops in my area. Nice score, by the way!
Mendon, set back on the left before, but near Imperial. Can't remember the guy's name, used to be in Boston, owns many old cars including a GS. He recently moved his shop to Mendon. Peluso Precision, on Facebook. Owned by Steve Peluso.
Steve Peluso is a real car guy. He was president of the Pontiac Club. He knows his way around GM transmissions for sure.
Tell him not to dip your transmission case in the tank to clean it if it has an ID tag like a turbo 400. When they get dipped all the colors get washed away. Ask him if you can clean it by hand.
ATS in Millis, MA. You won't do any better and their prices are fair. They will also build you a performance automatic if you are into racing.
Steve Peluso also rebuilds starters that look original but would crank a nuclear submarine from a cold start.
