There are 3 main variations.
The bearing width must be matched with the appropriate front drum.
LATE PUMP ASSEMBLY REAR - NOTE JOURNAL WIDTH TO MATCH BEARING WIDTH INSIDE FRONT CLUTCH DRUM.
THIS IS NOT A GOOD EXAMPLE TO PHOTOGRAPH - THE JOURNAL SURFACE IS HEAVILY WORN, AND SHOULD BE REPLACED IF YOURS LOOKS LIKE THIS.
The gearbox breather also changes style in 1974 to a plastic assembly, from a plain metal plate.