lookign for a 12 bolt!!

[Young11b]

Had my car into my step dads shop. Parts at the shops cost will cost me $1k to fix so Im looking to get a new rear end. I was looking at the 12 bolt but not sure the cheapest place to buy one from. I'm still looking to keep the 3:37 gearing. Im not sure really what I am looking at since I have no idea what a 33 spline or 30 spline is. If someone could help me out I would appreciate it. The mods I have on my car are headers, exhaust and CAI so Im not looking for the most expensive rear end to put in. With this new job I will be getting when I am out of the Army I will be putting $20k-$30k into it so I will be replacing it again. I just need it to hold up with the horsepower I have in it now. Thanks guys

[Firebirdjones]

Did you say you'll be replacing the rearend later again???

If you do a 12 bolt or 9" it should be the last rearend you ever have to buy no matter what power you throw at it.

My wifes rearend just bit the dust too. Over $600 in parts to fix her stock 10 bolt (my labor is free,,,sort of). So I decided to build a 12 bolt for it as we speak. Just a simple 30 spline setup.

If you don't have the means to build one then you'll spend about $2800 for a drop in unit ready to go. As far spine count on the axle goes.....the aftermarket 30 spline axles are non tapered and about 30-40% stronger than the OEM 30 spline 12 bolt axle. I believe math calculates they support 1500 ft lbs. each which is more than enough for any street car.

33 spline is simply overkill. Although it usually doesn't cost anymore to upgrade if bought all at once (as it requires a different carrier) so you see most guys just splurge for the 33 spline. It's a little bigger and heavier, and it's rotational mass that isn't needed (if that bothers you) But I'll stop before I get way too deep into this discussion .

It's up to you and what you want/have to spend.

[Young11b]

How you building the 12 bolt? My step dad is a mechanic so I get all the labor for free and parts at the shops cost. Do any of our sponsors sell the 12 bolts? I have been looking but came up with nothing. I went through Performabuilt and bought their 2 stage transmission. The only website I have found for a 12 bolt was Summit Racing. I am in the Army so I have the money to buy one though I will be broke haha. I do want a 12 bolt but I find them running between $2,700 - $3,100 and have no clue why the price is diffrent. What is the diffrence between the 12 bolt and 9"? Which should I get?

[pajeff02]

Two threads for the OP to take a look at:

http://www.ls1.com/forums/f8/how-pick-rear-125182/

http://www.ls1.com/forums/f8/bidding...-adieu-127890/

[2002ssslp]

If you have a 6M car I would go with a Mosier 9" or a Strange S60. Both are going to set you back over 3k but it will be the last rear you ever buy. These rears have options so that is why they differ in price.

[Firebirdjones]

How you building the 12 bolt? My step dad is a mechanic so I get all the labor for free and parts at the shops cost. Do any of our sponsors sell the 12 bolts? I have been looking but came up with nothing. I went through Performabuilt and bought their 2 stage transmission. The only website I have found for a 12 bolt was Summit Racing. I am in the Army so I have the money to buy one though I will be broke haha. I do want a 12 bolt but I find them running between $2,700 - $3,100 and have no clue why the price is diffrent. What is the diffrence between the 12 bolt and 9"? Which should I get?

It's up to you. Seems people follow the thought process of "6 speed = 9" or "auto = 12 bolt" I don't follow that theory myself. A 12 bolt built right is hard to break, even the local diff shop here that does F bodies will recommend a 12 bolt up through 1,000 hp. Depends on how you build it.

There are good and bad with either rearend design. I also like the 9" and use it in another car, great design, easy to build and tough too. It's a long going debate that I think has no end to it. You just have to pick what you feel comfortable with.

You are right that prices vary between $2700 and $3100 and even beyond that.. Your goals with the car will determine exactly how you want to option a rearend.

For example, I went with a 12 bolt for my wifes 6 speed SS camaro. With an Eaton heavy duty 30 spline posi, aftermarket 30 spline non taper hardened axles, C-clip eliminator with ford 9" housing ends. The housings themselves are cast much stronger than OEM 12 bolts ever were, and come with Chrome Molly caps (they won't break).
This rear will easily support 600-700 HP,,,which is overkill for my wifes car, it will never see that kind of power. I don't even see the need for a support cover so a stock cover will go on. The rear will now outlast the rest of the car. I can pretty much guarantee I'll scatter that 6 speed before that rearend even sneezes .

[Supershafts]

12 blt or D-60, either one from Strange.


I have recently done 2 different chevelles, one with a 598", making 800hp, on a 12 blt, the other a 572" making 730 w/2 stgs (400hp), neither broke the 12

[Young11b]

Thanks for the resposes everyone. Looks like I am going with the 12 bolt. Now all I have to do is order it this weekend if I want my car up and running by the time I get home for leave. I have been looking to order one from some websites and some of them require me to choose every option. Most of which I am unsure of so it looks like it will take me some time to order...

[Firebirdjones]

Some of them have a rather long lead time as well. Not sure what time frame you are looking at, just a heads up though.

Check Stranges website. You can pick your options, type of posi, spline count, C-clip or 9" housing ends, stock cover or support cover, 3 or 4 channel abs, stock yoke or 1350 yoke, etc....
You can even choose backing plates which may or may not be critical for you. If you choose the 9" housing ends your backing plates and the bearing retainers have to be on the axle before the axle bearings are pressed on. Strange will do this for you if you order new backing plates. Otherwise you'll have to do this when it arrives....If you use a stock C-clip setup it's a non issue. I wouldn't recommend stock C-clips though if you plan to throw alot of power at it... (even though I run that in one setup with alot of power)