i am looking to buy a posi unit for my rear end...but am not sure how many splines i should look for. It appears to be a stock rear end from my 84 z-28...if anyone could tell me what kind of posi unit i should look for. And also if it would make any difference, i plan on putting 4.11 gears in it

 

if it is stock... it should be 26 spline axles...

 

10 bolt i'm sure? but then is it gonna be a 7.5 or 8 Dia.?