Alright guys, the time has come for me to get a bigger rear end. I know this question has been posted about a 1000 times, but I have specific needs to fulfill. Right now my 95 Z w/6-speed is making about 308hp/330ft-lb @ the wheels. I want to be able to throw a rear on this car and never worry about it again. I daily this car in the summertime, but have every intention of slapping on some good tires and making a few passes down the strip as well. Eventually I'd like to build the motor for a blower, but I like having a backseat and access to it so however much power I add to this car it will never be enough for the track to require a rollcage. I guess I'm wondering how fast you need to be for a required cage and how much power you've got to be making, then if a 12-bolt can reliably handle that much power abusively or if I should bite the bullet and go with the heavier, less efficient 9-inch.

Edit: I am going to using a limited slip differential of some sort, no spools

 

For an M6 car that only makes occasional track pass, you would probably be best off with the 12-bolt up to about 750HP. Above that level, or with an M6 that gets raced every weekend, go with the Strange (Dana) 60 or a 9-inch. I like the Strange 60 based on a preliminary look, but there isn't much feedback from users yet.

 

Far be it from me to second-guess Fred's advice, but I just want to add some info:

I'm in a similar situation to the OP. A bit over 300rw right now, plans for more, and I want to upgrade it before anything goes wrong and never have to worry about it again.

Properly set up, a Dana 60 is the strongest of the three options. It's also the heaviest, at ~25 pounds heavier than a 12-bolt with the same setup. However, from the prices I've seen, it will also save you a couple hundred dollars over a 12-bolt.

As Fred said, there isn't much feedback from users on the Dana 60 yet. I'm not ready to buy, and I'll be paying close attention to what we learn until I'm ready. I've heard positive feedback from a friend of mine that has a 9-second supercharged 4th gen using a DTS Dana 60.

My thinking is that 25 pounds isn't much (<1% of the total weight), and I can spend those couple hundred dollars on other mods... maybe put it towards a tubular K-member and knock 40 pounds off the front of the car. So, unless we learn that the Dana 60 is completely inappropriate/unreliable/etc, I'm pretty sure that's what I'll end up buying.

 

Without big HP and big tires to stick it on the ground, the 12-bolt will suffice. Lighter and more efficient too. F-bodies are already heavy pigs, why add more weight if you don't need to?

 

That's what I'm thinking, too. 40 pounds off the front and 25 pounds on the back is a big step closer to 50-50 weight distribution, and I care a lot more about that than reducing total weight by <1%.

I'd love to get to 50-50 without adding any weight in the rear, but that's just not going to happen, especially without sacrificing many of the things I love about the car.

 

Would definately look into a 12-Bolt or S60 for your application. 9" are nice and pretty much everything roxy said above are there pros and cons. S60 does require some driveshaft mods or changes though...

 

Thanks for the replies everyone. I found an old post that Injuneer had made on another forum and he listed out a bunch of pros and cons between the moser and strange axles. I think I've decided on a 12-bolt from Strange. I like the fact that it uses all the stock equipment so I can keep my LCA relocation brackets and don't have to worry about getting anything special when I upgrade my torque arm and some other things later on. Does anyone think a 12-bolt with slicks behind a 550ishhp (at the engine), 6-speed have any issues?

Edit:
Here's the post
http://www.f-body.com/forum/showthread.php?t=10953

 

We;ve had good luck with both Mosers and Stranges 12 Bolt setups. Good info in that link though..

 

The only issues you'll have would be clutch or tranny-related. Your stock clutch (if you still have it) definitely can't handle that much power. The trans should be okay, but a basic performance rebuild with steel shift forks and slider keys would be a good idea.

 

I'm not worried about the clutch or tranny, at least not at the moment, right now I have a SPEC stage 2 on the car and can upgrade later if needed along with rebuilding the trans. I'm only worried about the rear (I'll get a new driveshaft too) because I'm going to replace it this spring and only want to have to do it once. I'm just saying in the future if I ever get the engine built to handle a blower or get a newer LS engine the most power I'd EVER put to it would be 550-600hp at the flywheel. I know the 12-bolt is rated to 750hp, but do they take a 6-spd with good tires into consideration with that rating?