I am going to replace a couple of Seals on my Fordomatic while I have it out of Car. The Front Pump to Case Seal is Ford # B1AZ-7A136-A. Its an "O" ring type Seal.  Apparently this Seal is applicable to 1951-1979. Was the original Seal Square Profile or round? All the Replacement Ones I see are Round Profile.
 Does the Round One replace the Original which I think was Square? I am replacing the Front Pump Seal as well as the Bushing also but those Parts are the same as Original. I assume the later Application would be for FMX not C-6 Transmissions? I am replacing the Manual Shift Lever O-Ring and Seal also.

  

This is just an opinion NOT A FACT but I assume Ford upgraded this as they gained more experience with use. Pete

PS DO NOT FORGET the two small O rings in the shift lever going into the side of the FOM case.