8 3/4...School Me...

Nice link, Demon Seed, good info.
CKJ688: The more splines you have, the heavier the axle will be, if it carries that diameter through it's length, which I would think it would, for strength. When I raced in Stock Eliminator, we used the lightest that would hold up., giving us a huge (sarcasm) advantage. Hey every little bit...
Also, FYI, Mopar "posi's" are referred to as "Sure-Grips". Doesn't matter a bit, they do the same thing!