Stop in for a cup of coffee

I checked my pile and I have a 3 904 transmissions I can use, which I know are good cores and there wasn't anything wrong with them other than being in parts cars or just not needed.

A 1972 ( I know least about this unit)
1974 out of a valiant I parted and is the numbers matching unit to the engine I am building
or a 1975 out of a running (at the time) 75 dart.

Is there much change over those years and any reason one might be better than another?