Flanker,hope this helps you out some.the 10-Bolt with a 7.5ring Gear common to the '82-94'Camaro/Firebird is the weakest.The'64-'72 10-Bolt Camaro/Chevelle/Nova measures 8.2 across the ring gear.The stongest of the 10-Bolt's is the 8.5 it came in a variety of GM models '70-'81 Comaro,Gto,Firebird '70-'75 ChevyII and'70-'76 Chevelle.Measure your ring gear to see if you have a 7.5/8.2/or 8.5.Ifyou have a 8.5 this is what it could have come out of,Buick Apollo'73-'77/Comaro'70-'81/ Chevelle'70-'76/ Firebird TA'70-'81/Grand National '84-'87/ Gto-Lamans '71-'77/ Impala '70-'76/ MONTE-CARLO'71-'77/Nova '70-'75/Olds F-85'70-'76/ Regal '73-'77 hope this helps you out.