There  are 3 main variations.

• Early style with a thin bearing area for the front clutch drum support. 1962 - 1970
• Later style with a wide bearing area for the front clutch drum support. 1970 upwards
• Later style with a wide bearing area for the front drum support, and for lock up versions of the 727.

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.