12 Bolt Gears/Posi - Question

[mphudak]

I'm looking at buying a set of used 3.42 gears and Posi/Anti-spin but not sure if they are for my 12 bolt/Type O. Seller is stating they are for the Type O but I'm questioning the carrier as it has casting # 762 and not 672. Can anyone confirm if these are correct or what they fit? I'm wondering if they are the BOP 10 bolt.

[monzaz]

How many bolts on the ring gear?
IF it has 12 that is for a FULL SIZE olds like a delta 88 98 etc.
You need the cutlass 12 bolt cover 10 bolt ring posi carrier.
The yoke spline on the pinion will be 27 spline
The full size pinion will be 28 or 30 spline pinion depending on the era 65-70 (28) or 71-76 (30)
ring gear most outer diameter for a 12 bolt cover 10 bolt ring is 8.5" where as the FULL SIZE is 9.3" in diameter.
We have listed a 762 carrier is a 12 bolt ring gear and 31 spline axles for a FULL SIZE car. it holds 3.42 -steeper gears.

If this does not work for you we might be interest in this unit for a housing we have on the shelf.
All these are for the 12 bolt cover and 10 bolt ring a-body gm rear
672 casting is for 3.42 steeper with 31 spline axles and 67 68 era
671 casting is 28 spline 3.08 -3.23
673 casting is 28 spline 2.56 - 2.78
588 casting is 28 spline 3.42 and steeper