The gears are the same dimensionally; except that the high volume pump gears are taller.

The later pump can be retrofitted into the older motors: the B21s and the B23s. It is standard on the B230s.

An exception to that is the B234F: the DOHC redblock. On that motor, Volvo used a gerotor type oil pump located at the front of the block, not in the block/sump area. The gerotor oil pump was such a wonderful improvement that Volvo stopped using it when they discontinued the B234F. [sarcasm intended]