Understood. Finding someone that is still alive that worked on these transmissions is getting difficult. There are several manuals on-line that cover GMC H-M identification, 54 Chev H-M service, Adjustment and service manuals.
You mentioned much conflicting information. At this point, it is easy to find people that will tell you what they think they know and tell it with authority. That just makes the project harder.
If it makes you feel any better, I have an old transmission service manual and it lumps all H-M transmissions in one chapter. In my mind, that would lead back to my statement that if it fits, it should work for you but I am not willing to stick my neck out and say that for positive.
