I have a posi unit out of a 1978 Buick LeSabre. It is a 10 bolt, 30 spline pinion, I know there were no "C" clips on the axles. They bolted to the end of the differential. Casting number on the posi unit is 410409N. I believe it is a 8.5" but the guy that installed the ring and pinion 10-12 years ago thought he remembered it as a 7.5. It is tough to measure with the ring gear installed and the differential is long gone. Once I figure out what this is I will put it up for sale. Has a Richmond 3.90 ring and pinion set.
Try to put 2 pieces of wood ( or a straight edge of some sort) on the opposite edges of the ring gear and measure the distance between them.
I don't mean to highjack your thread but I'm looking for the sidegear or gears( a set) for a 8.5. One of the sidegears on a 8.5 posi I have is badly pitted!! Anyoneo No:
