When did the 10-bolt ring gears go from 7-1/2" to 7-5/8"? The Helm says 7-5/8 for '85, but the gear that was in there was 7-1/2" with a GM part number. (The original gears were 3.23, since it was an automatic and I don't know where the 3.73 gears came from.) When they were replaced with new Richmond gears, the box said 7.5 but I didn't actually measure the ring gear. Maybe I will when I change the oil sometime.

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1985 Yellow IROC-Z 5.0 HO, T-5 3.73 Torsen, 4 wheel disks
PFCM pads, GTA wheels, Koni yellows, B&M Ripper, Dynomax

 

They both work on the same carrier and are basically the same strength. The Richmonds stronger than stock gears anyway and I think they are 7.625 when measured(but not sure).


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350 with stealth intake, holley carb, 470 lift cam. 700r4 with .5 boost valve, vette servo, tci lock-up kit, B&M megashifter. Richmond 3.73 gears, powertrax locker, timkin bearings, synthetic lube. Custom 3 inch single into 2 2.5 pipes. 1 1/2 drop springs, 1 5/16 solid front sway bar, 1 inch rear bar, custom subframe connectors, custom LCA relocation brackets. Kobel ground FX, current red metallic paint. Lots of other stuff...
82camaro

 

Even aftermarket gears are still called 7.5 even though they are 7.625. 7 1/2" is just a generic term labeled to our diff. Both will fit on the same carrier.