Hughes highstall convertor??,s

The trans could actually be a 999. which is a 904 with a 5 clutch front drum. 904 came with either a 3,4, or 5 clutch drum. Just above the pan rail on the drivers side there are numbers stamped in the case. If you can post those numbers I can tell you if its a 999 or not. I don't believe the lock-up trans started until 1978.