The full size blazer had the 8.5 rear end, but the housing ends were larger, so the brakes wouldn't bolt to a car rear end. The Camaro rear end is the little 7 5/8 10 bolt, but the brakes will bolt to other car rear ends. The S series trucks had 7 1/2, 7 5/8 and 8 1/2 rear ends. The 4.3 5 speed trucks has 8.5 rear ends, but the axle tubes are tapered down to 2 5/8 instead of 3 inches. The S series truck disc brakes had the internal shoe parking prake.
None of these rear ends will fit your car, but you can use some of the brakes. The only rear ends that will fit your car are the '73 to '77 Monte Carlo, Malibu, El Camino and other GM clones of these cars. Nothing else will bolt in without a lot of modifications.