chieftransam

I'm curious of how many m6 guys are running 12 bolts. I just got a 12 bolt for my car (m6). I got one with 33 spline, lca relocation brackets, 3 channel, and 3.73 gears. Are there other's out there running the same or something different? I got a friend that has a 12 bolt in his car (m6) cutting 1.30 60's. So I figured if it's strong enough for his car then I'm pretty sure it'll last in mine. I almost went with a different gear ratio, but decided not too since my car is a dd and see's a lot of highway and in city driving.


I also ordered the spohn 405 torque arm (for lt's and y pipe) w/ the front ds loop, and I'm getting a custom made ds also. I already had the sfc's, stb, and lca's so I'm praying I can run somewhere in the 12's . I'm sitting at 415 hp and 395 tq. I got some m/t et street's to throw on once its installed next week. Any ideas on possible times in the 1/4?

BlackScreaminMachine

iTrader: (17)

I run a Moser 12 bolt, Had originally been in my 94 z28, ran with a 3.42 gear, actually w/ bolt ons ran better at the track then the 4.10's but thats due to that I can leave in 3rd to the end of the track.

As for strength, these rears can def cut good 60 foots but that has to do with alot with the combo/suspension/weight/ traction.

IROC test mule

The weak link in the 12 bolt is the ring & pinion. In any drag racing application you can expect to replace the gear set every 1 to 2 seasons. With the quality of gear sets nowdays you'd be taking your chances using a street gear on any racing application. I used to race a Super Stock ChevyII in SS/D (4 speed) and the gear in that was only good for 1 season. Being yours is a DD you might be ok if you didn't race it. Take it to the track with drag radials and the M6 trans and you can expect problems. plus it's a heavy car to boot! The bad part about it all is that most gears are made overseas now. The better ones come from Italy but you never know where they come from. If you were building a "race only" car I'd reccomend running a "pro" gear. they're not as hard as a "street" gear and can handle higher shock loads. As i said before, the ring & pinion will be your weak link. I'd use a 9" with a M6 trans if you are buying one. Make sure it's from a reputable source, not just the cheapest guy out there. And make sure you tell them what your plans are for the rear end so you only have to buy once.

ndfrsd6

iTrader: (5)

I have a 402 with over 500 rwhp and a 6spd w/4.56 gears , strange 12 bolt and i've had no problems ......I cut low 1.5's looking for 1.4's with suspension tuning tire pressure ect....

keliente

iTrader: (22)

I had a M6 with a 12 bolt. If I had to do it over again, I probably would have gone with a 9 inch. After one launch with the 12 bolt it made a llllllllllot of noise.

EPP

iTrader: (22)

I did the same thing back in '02, one night at the track and it got noisy. Bob

99SilverZ

iTrader: (13)

Running about the same thing as you. I'm running 4.10 instead of 3.73. In your case, as a DD, 3.73 would be better. If you are not going to the track often then don't expect low 60' times. Regardless of your setup, your 60' time won't be consistant unless you run just about every weekend. I have a buddy that makes 1.4 to 1.6 60' on a stock rear (M6).

EPP

iTrader: (22)

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.

Exotic Performance Plus strongly recommends the Moser nine inch. This rear is even tougher than the Moser 12 bolt, and the horsepower of the late model F Body cars keeps escalating every year, which requires a very strong rear. With the recent introduction of the 6.2L GM aluminum block and the excellent flowing 6.2 litre heads, the horsepower of these cars is going to just keep climbing at a very fast pace.The nine inch will handle the power, plus we prefer the way the torque arm is bolted to the nine inch in the same way the oem rear-end is attached. (This is the only good thing about the stock 10 bolt...) The Moser 12 bolt uses four short bolts to attach the torque arm, and they have a habit of loosening up, even when loc-tite is used. Why the nine inch is stronger than the 12 bolt. The 9-inch has an internal rear-pinion support that also supports the gear end of the pinion to limit gear deflection under high torque loads. This seems to be the major reason why the 9 inch doesn't start whining after high rpm clutch dumps, when the 12 bolt will pick up noise.The 9-inch locates its pinion gear lower on the ring gear to improve tooth contact, than the 12 bolt does.The 9-inch has a 0.125-inch larger ring-gear diameter and internal pinion support than the 12 bolt does. This is not much of a difference, but it is worth noting. Bob