GM 11.5  
14 bolt rear cover with 11.5" ring gear. Does ot have a removable pinion support on the front of the housing. Uses bolt in full floating axles.

GM 8.875 Car  
12 bolt rear cover with 8.875" ring gear using 12 ring gear bolts. Has 30 spline c/clip axles.

GM 8.875 Truck  
12 bolt rear cover with 8.875" ring gear using 12 ring gear bolts. Has 30 spline c/clip

GM 10.5  
14 bolt rear cover with 10.5" ring gear. Has full floating 30 spline axles and a 6 bolt removable pinion support.

GM 7.5  
10 bolt cover with 7.5 ring rear. Uses 26 spline c/clip axles.
GM 7.6  
10 bolt cover with 7.6" ring gear. Uses 28 spline c/clip axles.

GM 7.75  
9 bolt rear cover with 7.75" ring gear. Uses bolt in axles.

GM 8.0  
10 bolt rear cover with 8" ring gear. Has 28 spline c/clip axles.

GM 8.2  
10 bolt cover with 8.2" ring gear. Uses 28 spline c/clip axles.

GM 8.5  
10 bolt cover with 8.5" ring gear. Ring gear has 10 bolts and pinion has 28 spline.
GM 8.6  
10 bolt cover with 8.5" ring gear. Hs 30 spline c/clip axles.

GM 9.5  
14 bolt rear with 9.5" ring gear. Has 33 spline c/clip axles. No removable pinion support on the front.

GM BOP  
10 bolt rear cover with 8.2" ring gear. Has bolt in 28 spline axles and a 27 spline pinion.