If the trans is out on the bnech you can put it in 5th and turn the output shaft 10 revolutions and count the turns on the input shaft (so a .82 OD would then be 8 turns +.2 or roughly a quarter, if you have the 1o spline input that's real easy as it's 8 turns + 2 splines, if not, guestimate, it's close enough).
You probably already know that, but I thoguht it might help if you hadn't (old dirt racer's trick I was taught).
