85 442 whats the spline count & a decent posi unit

[youngdeezy]

Tomorrow i'll be picking up a 8.5 from a 85 442 with 3.73's and non posi. I would like to add a posi unit and im unsure where i should start looking. i know i can buy the item from summit, jegs, ebay etc. but what spline count should i be looking for. i never got into the posi thing before i know eaton and auburn carries what i need so maybe a little help from you guys can clear things up for me. For some odd reason im a little slow understand this so if anyone has some extra time to say something drop me a part # for the item if you can. thanks

heres my car info im not sure if that will effect the type up setup i should buy.
83 cutlass supreme
pretty much a stock LT1
th350
8.5 rear with 3.73 non posi but not for long (hopefully)

 

[Blake442]

Stock for the 8.5 is 28 spline.

 

[youngdeezy]

Thanks Blake. I figured it out once I got off my iPhone and was able to do better research on the laptop