Join Date: Jan 2000
Location: Houston, TX USA
I no not believe that a 3.42 gear will ever work on your 4 series carrier. The reason is that the flange that the ring gear bolts to is too close to the pinion. As you go numerically lower, the pinion gear gets larger. With a 3.42 the pinion gear will be almost touching the flange on the carrier-even before the ring gear is bolted on. So, to answer your question, NO, I don't think there is a company that CAN grind you a custom set of gears to work on your 4 series carrier.
You would be better served by selling your 4 series carrier, and then buying a 3 series. As you may know, you can always run 4 series gears 3.90 & up, with a ring gear spacer on your 3 series carrier. You CANNOT however run 3 series gears on a 4 series carrier.
1969 Camaro SS 350-383ci., T-56, 12 bolt, Eaton posi, 3.31 gears, 4 wheel disc, Deluxe black houndstooth interior, rear window defogger, tilt steering, console w/AutoMeter gauge package, center mntd. clock, Tach.