This is from the 1967 Chevrolet-Chevelle-Camaro-Chevy II (Nova)-Corvette Chassis Overhaul Manual, telling you how to fix the 10 and 12 bolt Chevy rearends. Enjoy!
And here's more....from the 1982 Chevrolet Impala-Caprice-Malibu-Monte Carlo-El Camino manual, referring to the G body 7-1/2" rearend and the B body 8-3/4" rearend.
and here is a general rearend gear setup guide from Yukon Gear, in pdf form
