I'm expecting to have approx. 400HP and from my ZZ4. What rear would best suit my needs? And which cars could I find one at a local salvage yard. Thanks in advance...

Toney

 

You won't find a 12 bolt in the junkyard that will bolt in. I would stick with the 10 bolt and a AL rear cover upgrade to 28 spline axles if you don't have them already. Or just wait until it breaks and spend the $$$ 2 grand for a 12 bolt.

I broke a 9-bolt in my GTA while it was running high 14s on reg. street tires. The newer ('96) 10 bolt replacement and original one in my TBI car have been fine. There are some advantages to the 9-bolt but I sure wouldn't go seeking one out. When I looked for gears it was like $500 a set for just the gears compared to ~$200 for a 10 bolt.

 

yeah alot of people like the fact 10 bolts seem to be alot cheaper, i say build up the 10 bolt as mush as possible.. and then when / if it goes go with a 12 from moser..

https://www.thirdgen.org/newdesign/t...nguprear.shtml

https://www.thirdgen.org/newdesign/t...nguprear.shtml

 

That would have to be a fluke. Was the carrier already going out?

www.diffsolutions.com

This guy has a big block running 1.7 60's and is running a 9-bolt. He is selling parts to guys that are running 1.6 and 1.5 60's. You can build up a 9-bolt to be strong enough for bracket racing, for half the price of that 12-bolt from moser. Or anyone at that price.

 

The 9-bolt rear made no noises, the posi wasn't the greatest but worked fine, it had ~90,000 miles on it. I ripped of numerous teeth off the ring and pinion driving on the street, my best 60' was in the 2.2x range.

To me the prices of built 9-bolt from that site are:
$300 gears
$450 posi
~$250? axles standard 10 bolt price.
~$100 install kit
$$$ Labor?
~$300-400 for a used 9-bolt axle

That's $1500+ For ~$2200 you can get a built 12 bolt. A lot of LS1s go pretty fast (11s) before breaking their 10 bolts. This guy is only talking 400-450 hp. Maybe if you already own a 9-bolt it might be worth it to keep it, but I wouldn't go seeking one out.

 

Actually I got a mag. with a 4th gen camaro with around 500-600 hp out of a sbc (massive cam and stall) it was running a 9 bolt I think. I'll try to dig article out sometime.

 

9 bolt...ez to build up and a ton cheaper than the 12 bolt.

 

Ok, I dug out article in HPP July 2002 LS1 with no blower or juice all motor. It runs 10.98 on a factory issue 10 bolt... It has a 4.10 motive gear but they said what helps from killing the rear end is setting the backlash around 10 thousandths instead of normal 7-10. It has a 4400 stall on it. It dynoed over 400 hp with just a head change... that was before they swapped cams or anything else so it makes a little power.

I still say 9 bolts are nice. I've heard people say they've ran high 11s on them before without any problems.

 

The strength in 3rd and 4th gen 10-bolts are way different. If you want to get a 10-bolt off of the 4th gen, go for it. Just get some wheels while you are at it. Oh yeah, weld the tubes, get some gears, a new carrier, and some axle tube seals. About the same price as building up a 9-bolt, once everything has been done. Or you could make it look like a *******, Louisianna car with wheels that stick out 2" on the rear.

A 10-bolt rear out of the 3rd gens can be torn up by some 350s stock. Why else would they put the rears in?

Here is what the guy that sells/swears by the 9-bolt runs:

ET 12.18, MPH 113.10, 60' 1.75 with 3.27 gears
500hp and 520ft/lbs

 

Just saying if they run the backlash that loose to help lubrication, then it would probably help a 9 bolt too. I have a 9 bolt with my 2400 9.5 ACT stall. My friends old malibu (carb 305 with turbo-350) use to blow 10 bolts all the time... he went through 3 of them from the time I bought my formula to the time he finally sold off his car. I didn't have any trouble with 9 bolt at all.

 

Thirdgen 89+ 10-bolts are the exact same thing as 4’th gens. The only difference between the two is the 4’th gen rear is 2 inches longer on each side. The Trosen POSI unit in the LS1s adds a little strength over the 3’rd gen 10 bolt. The 82-88 10 bolts have 26 spline axels so they are a lot weaker then 4’th gens.

I still feel the strongest 3’rd gen factory rear is the dana 44. But they are hard to find.

 

Very true. I forget about the 89+ version. Still for what it takes I think he has his answer.

 

The 12 bolt has the potential to be considerably stronger than the 9 bolt due to the fact that components are larger and there are more HD aftermarket parts to choose from. Obviously a 9 bolt is plenty strong and did get put in the later 80's thirdgens like the L98 cars and Turbo TA. The 10 bolt was used more, but on average it wasn't as strong (except the 28 spline 10 bolts).

One thing to keep in mind is that I never heard anyone breaking and axle in a 10 bolt rear unless is was totally dry (no lube) or if the rear was not set up correctly (pretty rare too). Typically a ring gear loses teeth (66% of the time) or a pinion loses teeth (30% of the time) or you spin a bearing (3% of the time - I did a pinion bearing). I haven't heard of too many 9 bolts blowing up, but no one I know had a car with enough power to do so.

The 12 bolt is one hell of a strong rear in stock form - GM used them in big trucks and big block muscle cars for many years. Built up they can be used in almost any race application a 9" would be, except the rear is not as friendly to gear changes. I have a Strange 12 bolt in my Camaro - I got the one with the street posi and it was said that you could run a car into the 8's without worrying too much about blowing it. The strip posi has bigger axles and is packed with more clutches for even faster cars.

If you are gonna be under 450hp and not use slicks, try to get a 9 bolt. If you are gonna throw more power into it, buy an aftermarket 12 bolt.

 

Thanks for all the info guys. I don't think I really need a 12Bolt after reading your comments. I have a 10Bolt but I didn't want to break it while I'm away from home. I think I'm going to stick with my original idea to go with a 9Bolt. There's several at a local salvage yard for only $100.00 complete.