As part of an "Increased cooling package" the front pump was changed in '74, the most noticeable change is a reduction in the size of the cast counterbores in the pump housing and the reaction shaft support; this provides more seal off area for the face of the inner rotor.
At the same time the front clutch lube orifice in the reaction shaft support was eliminated, so a '74 and later pump has some good features and some bad (IMO).
I always drill the lube orifice when building a '74 or later 727, this requires an extension drill.
Also, it's important to keep the '74 and later input shaft with the like-year reaction shaft support as there are differences in the bushing lube ports.