[Mike Taylor 3601]

Can figure pinion depth using master housing dimension.
Measure pinion head thickness -(where bearing sets against pinion to back of pinion,same place you check center distance from) then subtract pinion head thickness from master housing dimension,that will give pinion depth checking distance.
Can't remember 12 bolt master dimension off top of my head,but you can find easy on line or richmond tech line etc.
Mike Taylor 3601