I called Blumenthal's in Oklahoma City a few months back about some driveline parts. I was transferred to the elder Blumenthal (owner-I can't recall his name) since it was for a vintage truck. He was curious about what I was working on and after discussing it he stated that they have the capability to rebuild these older transmissions. I know you're not necessarily asking to go this route and I can't vouch for them at this point except for their name and longevity in the community, but since you'll probably have shipping even on an old one, you might want to call them and just see what the rebuild would cost (405-212-3065).
