1950 Cadillac - looking for a shop to fully rebuild and test the transmission

[cdub]

as the subject line states

My 1950 Cadillac has been being "worked on" for about 6 months now.  The trans has been in and out several times.  The local shop tried to rebuild it themselves, but can't seem to get it working.  I'd like to find someone that actually knows what they are doing and could rebuild the transmission and test said transmission prior to returning it.

A while back I saw a company advertising in the "Self Starter", but now of course I can't find it.

Any recommendations?

[Clewisiii]

I used Classic Hydromatic.  At the time he was in Plymouth MI. But he has moved to Nortb Carolina.

https://www.classichydramatic.com/

[chelonian]

I had a hard time finding anyone who knew how. Finally found Lake Sumter Transmission in Leesburg, Florida. Lucky for me they were not that far away. Cost four grand. Brought them the whole car. They also had a hard time, had to go into it twice if I recall right. That was 3 years ago, no issues.