HD 4spd. Tranny ID#

[chauncy]

I have a few transmissions with various stamped numbers. How can I tell what year they are? One has E2 and a case vent. One has E2 and ratchet top vent. One has a ratchet top vent and only 121-35 stamped on it. The last one has C.C.C. stamped on it or it could be O.O.O. with ratchet top vent. Any help would be appreciated.

[Rubone]

Chauncy,
Not sure what you are referring to by ratchet top vent. Do you mean the hollow screw? A picture of each case with markings is the best way to get them identified.
Robbie