12 bolt?
the ring gear is either 1/4" or 1/2" smaller in diameter on the 12 bolt. 6 speed cars break 12 bolts "more" because the shock from launching rips teeth off the ring and pinion gear as opossed to the constant force of an automatic. if you got a 12 bolt with a spool, 33 spline axles, 4.10 gears and a 9inch with the same options the 9 inch is stronger because of the ring and pinion gears.
The Moser 12 bolt torque arm bracket uses four small bolts, and they are prone to backing out. We use Loctite on them and we still have to watch them.
The Moser 9 inch uses the oem method of two long bolts to attach the torque arm, and once tight, they don't loosen up.
Put a 12 bolt into a early Chevelle, Nova, Camaro, etc and you can beat the crap out of it, and not hurt anything. Put one into one of our cars with a torque arm, make a couple 4000 to 5000 dragstrip launches, and I can just about guarantee you'll pick up gear noise. If it is a drag only car, you'll never know or care about the gear noise. Drive your car home from the track, and the noise will drive you nuts. I feel the torque arm stresses the 12 bolt housing, causing distortion. We have never seen this happen with the 9 inch housing. Bob
The Moser 9 inch uses the oem method of two long bolts to attach the torque arm, and once tight, they don't loosen up.
Put a 12 bolt into a early Chevelle, Nova, Camaro, etc and you can beat the crap out of it, and not hurt anything. Put one into one of our cars with a torque arm, make a couple 4000 to 5000 dragstrip launches, and I can just about guarantee you'll pick up gear noise. If it is a drag only car, you'll never know or care about the gear noise. Drive your car home from the track, and the noise will drive you nuts. I feel the torque arm stresses the 12 bolt housing, causing distortion. We have never seen this happen with the 9 inch housing. Bob
