I am about to order a moser 9" for my camaro, and am fighting myself about 31 or 33 spline axles. I am leaning toward 31 for easily accessible parts. This is a street driven car that will be raced every couple of weeks. The setup is a stock engine with a procharger right now, but the blown 396 setup is in the works. It is a 6 speed car with a spec stage 4 clutch. Right now with 3.42 gears it runs around 12.5 @112. I have a spare hogs head that will hold 4.56 gears for the 1/8 mile with a mini spool, and the normal carrier in the car will be somewhere between 3.70-3.90 with a positraction.

I guess what I am asking is, will 31 spline hold it? Also, do they even make a positraction unit for 33 spline?

Sorry for the long post, and thanks for your opinion.
Stevie

 

You should be fine wiht 31 spline axles but if your going to go thru the troulbe of changing center sections just to race you can always change axles also. Moser does not offer a 33 spline limited slip diff (at least they didnt when i ordered mine). They do offer lockers in 33 or 35 spline though so you can always get one of those so you dont have to change it when you want to race.

 

You'll be fine on 31 spline axles with a 26" tires but if you go to a 28" m/t et drag or similar I'd opt for 33 or even 35 spline to be safe. An m6 along with a grippy clutch can put a lot of stress on the driveshaft and rear end.

 

Moser sells readily available 33-spline posi's for about $450... I think they're Eaton's.

 

Moser said there were no 33 spline posi's available. I ordered 31 spline, I don't think I will have trouble with it......I hope

 

I run a 31 spline...1.45 60s in a 6 speed on 28" slicks. No problem after 2 years and many many high rpm clutch drops.

 

Sweet, thanks for the reassurance. 1.45's are killer, I would be happy with a 1.7

 

Oops.. I meant strange... My friend just got in a 3 series 33 spline from them.. They regulalry stock it though.

FWIW - I'm running 30 spline and am holding up okay as well