Like the Borg Warner R10s, these were being converted for torque tube drives. A lot of them came from Volvo cars. They may have been used in early Ford V8 conversions as well. There is not a lot of information out there. I'll have to dig around and see what I can find. Hopefully an owner or operator of one of these will offer up some information.
This is a good link:
https://fordbarn.com/forum/showthread.php?t=247462