[Tom Goldman]

23 spline to early '69 then 35 spline .
Both 11/2" dia. ...For a street/ race car I'd use the factory posi.
The 6 gear posi is a brute weight wise,but very strong , I'v rarely seen a broken pinion or spyder gear.
I used to add a second bevel spring plate to the pack to increase the clutch pressure. ...A little choppy around turns if you were going slow.