rear end advice

**chadkesterke7** · 01-09-2013, 12:01 PM

Hi im new to this site. That being said im looking to be swapping out the 10 bolt underneath the car for a 12 bolt. Im not sure what to go with. The cars a 2001 Pontiac firebird ws6. Has a m6. It has a few mods. It has rear control arms, panhard bar, and subframe connectors all umi performance. Im not an idiot when it comes to cars just looking for advice. The car will be daily driven and occasionally see some track time. I was looking at summit racing for rear end assemblies. Any advice or success stories would be greatly appreciated thanks.

***SMWS6TA*** · 01-09-2013, 12:27 PM

Check out Strange, Moser & Mid West Chassis.

They have good reps & prices. Depending on budget and how much work you want to do your self you can have one for about $2200-2500.

**chadkesterke7** · 01-09-2013, 12:44 PM

Ya thats my budget 2200 to 2500. Ill definitely be putting it in myself. I just dont know what gear ratio or axles i want. Ive heard horror stories about guys blowing up those 10 bolts. Mines already had all new bearings put in it. Ive been though two pinion seals already. Still a little seepage but ill keep an eye on it.

**35th-ANV-SS** · 01-09-2013, 12:54 PM

Gearing will depend on what your long-term goals are for the car. Are you keeping the motor stock? Upgrading the cam? In general, naturally aspirated LS1's that are a M6 respond well to a 4.10/4.11 gear; Moser has the 4.11 set-up.

If you are doing something like adding a turbo or supercharger, you want a higher gear; 3.42 or less even.

Your car came stock with a 3.42, which you probably already know.

I personally have a Moser 9" TruTrac set-up with 31 spline axles and a 4.11 gear. I've had it installed about 5 years now. No issues to date. 2 of those years I have been pushing 500rwhp through it. 1st gear is pretty useless now for me though being I added FI. I have to shift FAST.

**Too Fast** · 01-09-2013, 02:16 PM

All good advice above.

Some people have good luck with their OE 10 bolts, running high 11s with sticky tires, and some blow them up with stock power/stock style tires. It's a crap shoot from what I've observed. Personally I've made quite a few trips in the high 12 sec range with street tires, and at 120k with no problems on the stock diff. Must have a good one! I do have a diff girdle and I've welded my axle tubes to the center, but I'm not putting any other $$$ into it.

**pajeff02** · 01-09-2013, 04:41 PM

Moser 12 bolt here. Details and a ton of pics in this thread: http://www.ls1.com/forums/f8/bidding...-adieu-127890/

**cpop98ws6** · 01-09-2013, 04:55 PM

Strange S60 here with 4:10's. I threw a lot of beatings to it since i installed it last year and it never missed a step.

**Knight** · 01-10-2013, 04:34 AM

I run the same setup as Jon does, and can't complain either. With a M6, 4.11 gears are about the perfect setup IMO. A4's will usually run a 3.73. But as Jon said, your overall goal for the car will be the biggest factor in determining gearing.

**chadkesterke7** · 01-11-2013, 06:47 AM

O ok thanks guys ill have to seriously think lol. Ive got other things that need to be done this winter. Since we haven't had much of one at least mi. Like i said though it does more cruising then anything. Buying this car has been a great investment haha.