7.5 inch or 8.5 inch

how do I figure exactly which rear end I have? I think my choices are either the 7.5 inch 10bolt or either the 8.5 inch 10 bolt (gm)

the vehicle is a 94 s10 with 2.73 rear end looking to change to 4.10

thanks

Although all s10's except the ZR2 came with the 7.5 rear, the easiest way to tell them apart is by the 4:00 & 8:00 positions as viewed straight at the cover. The 7.5 has little "fangs" where the 8.5 has larger triangles. The 7.5 had 26 splines before '88?? I think that was the year they changed to 28 splines.

thanks for info