8&3/4 spline count Q

here's the whole break down for coarse (10 spline) and fine spline (29 spline)
742 (1964 to 1972) - 1 3/4 pinion coarse
741 (1964 - 1972) - 1 3/8 pinion fine
657 (1957 - 1964) - 1 3/8 pinion coarse
489 (1969 - 1974) - 1 7/8 pinion may be coarse or fine