Hey folks,
I've been here before, I left because of the Bonneville rulebook, but I've been driving an '83 RX-7 I completely rebuilt with no Mazda parts remaining.
The relevant bit being I got the rear axle assembly from a 4WD '94 S-Blazer, took the guts out, got 2 LH 28-spline axle shafts from late-'80s Bronco 2s, got a 2-series 28-spline Auburn from a '95 Z28 automatic, with the standard 2.73:1 ratio, and I got some 2.29:1 7.5" gears off eBay for $60 shipped. I also got a 2.41:1 set just in case.
I tried this with the 3.8L V6 and T5 from a '96 Camaro, that T5 has a 3.75:1 first and a 0.72:1 fifth.
Only now I'm turbocharging it, putting the closer-ratio V8 gearset in the T5, and going to some 2.73:1 gears. This car is on 225/45R15 BFG Rival S autocross tires.
So I no longer need, and am willing to part with, both my 2.29s and my 2.41s.
Now, I'm putting together a turbocharged 454 in my red '86 Camaro hardtop, backed by an SM465 with the rare 1.5" input shaft, I just ordered it a new 12" clutch yesterday. If it slips I know where to find a dual-disc from a '69 L88 'vette.
Anyway, the big-input SM465 is heavy and poorly geared, but it is unbreakable. And it has no OD.
I was googling the 8.75" axle, and plenty of references to GM '70s big cars, but no details on exact year/model/engine?
I don't need that for crawling under, but I do need it for phoning around. I already crawled under every car in every yard around, that lets me pull my own parts.
I'll be welding the diff, once I get a 30-spline version. At the dragstrip I'll be trying 345/40R17 Toyo Proxes TQs on 11s, and at TRC I'll try Bridgestone Scuderia 345/35(Y)R19s on 12s