513camarors91

iTrader: (1)

i am getting all my parts together but i am putting a ls1 t56 into my 91 camaro rs. it now has a open rear end with drums and i want to put a posi rear end with disc on it. now my question is should i find a rear end out of a z 28 that has disc on it already or should i put a 4th gen 10 bolt 3.42 posi rear end in it. i know the 4th gen is wider but i cant remember how much wider. and i want the rear end to be able to hold the extra power its going to have. the motor will have cam head work and long tube headers when its all complete. thanx ahead of time

Anti-Venom

BW 9 bolts are rumored to be slightly stronger than a 10 bolt 4th gen rear. However there's no aftermarket support what so ever. The 4th gen rear can ultimately be built to be stronger overall. 4th gen IMO is the better choice it's 2" wider per side so depending on your rim choice could avoid you having to buy wheel spacers.

Both choices will not last under hard launches and I would save up and buy something stouter if your even considering a stick shift or slicks. Babied they will get you by. But who wants to build a stout motor and have to be nice to avoid blowing out an inherently poor rear end.

five7kid

iTrader: (14)

The 4th gen rear is just as weak as the 3rd gen rear. Because the 4th gen rear uses the same weak 7-5/8" carrier that 3rd gens used.

Get familiar with "9-inch", "12-bolt", and "S60". And with the feeling that comes from parting with about $2500.

Anti-Venom

Let's put it this way, I blew up my "9 bolt"" not 9 inch" BW with a mild bolt on tpi on slicks with 245hp and around 300lbft. They are super weak. Five7 speaks the truth.

five7kid

iTrader: (14)

There is an article in the latest Hot Rod Magazine about a guy who bought a '99 Camaro, LS1/T56, and made a race car out of it without touching the longblock. One thing he did do was install an S60 - after breaking a 12-bolt.

He has it in the 11's with tuning, weight reduction, intake, suspension, etc. But broke a 12-bolt with a stock longblock.

I went with a 9". Wish I had known about the S60 (it may not have been available at the time, though).

Anti-Venom

I've had to re-weld the tubes due to the tube to housing welds cracking on a couple. Otherwise S60's are stonger than a 12 and lighter than a 9 inch.

What people generally fail to realize though is there are a lot of variables that may stress a rear end and " What's going to live?" Can be a subjective question. Stick or auto? Auto generally won't shock the rear as hard. Street tires or slicks? Again, same principal. Car weight? Lighter car isn't going to be as much inertia to get the car moving. Is your suspension tuned to allow your car to hook?

What even is your intentions with the car? Track days on the roadcourse, Weekend 1/4 mile car? Street car that will only occassionaly get driven hard?

I have seen stock motor bolt on T56 cars kill 10 bolts on street tires. On the other hand I have seen a low 11 second, fully gutted, 600hp on a 150 hit on 10.5 slicks and trans brake car run for seasons on a stock 10 lol!

BlueZee28

iTrader: (30)

I broke a 4th gen 10 bolt at the track with drag radials....in the water box. Now has Ford inside.

88 350 tpi formula

iTrader: (9)

ALOT has to be said for the condition and setup of the rearend. a good 9bolt is a very strong rear but your always limited by its ring and pinion diameter. they have axles and a rear cover for the rear, solid pinion spacer many things to beef it up.

the dana 60 is a very nice rear. Im glad I went with it over the 9" . even though it weights more the larger ring and pinion is worth the extra weight

1nasty86

iTrader: (5)

8.8 here.. along with bluezee28. things held its own, moser axles, stock exploder center chunk with 3.55's.

Pocket

iTrader: (24)

Same here 8.8 with a 3.55 center section. Weakest link is the 10 bolt axles and they're holding up so far. The $100 axle that could!

fast377

iTrader: (4)

Custom job? Or is someone making one for our cars now? I want one, so I can keep my weight down vs. a 9" or 12 bolt.

EDIT: Nevermind...I found your build. I might have to look into that myself. Seems pretty straight forward, and I already have a 4th gen rear under my car. I wonder if any of them come with a good diff? Is the mustang housing any different?

BlueZee28

iTrader: (30)

Cam- made my 8.8. He used an explorer center section and 9" axle tubes cut to 4th gen width. Moser axles, Ford Racing 4.10 gears and trac-loc (Cobra part number with upgraded carbon fiber clutches).

UnstableAviator

Buying the 9" is probably the best mod I've ever done to my car. It was the first part I ordered when I originally bought the chassis, and I've been running the same 4.11/Posi for nearly a decade with 0 issues. If you can swing it financially, you will NEVER regret spending the cash.

When I'd drop the clutch on my old 383 at the track, the though of rearend durability never crossed my mind. Sure makes track days and even street driving a lot more fun.

Pocket

iTrader: (24)

Yep, custom

Car axles and light truck, mustang, crown vic, ranger 8.8s are 28 spline diffs and not many were posi. Reuse the stock 10 bolt axles for these. Axle tubes are thinner walled too so they slide right over the 10 bolt tubes. Truck 8.8s like the F150, Explorer etc used 31 spline diffs and require aftermarket axles. Most explorer axles are posi with good ratios 3.55-4.10. Tube walls are thicker so you'll have to turn the 10 bolt tubes down some or just grind away a little material. Its like .040" too big

tylercamaro

iTrader: (1)

9 inch all the way. my buddy has one in his 9 second nova and the thing is damn near indestructable, engine and trans went 3 times before he decided to refreshen it

cam-

The 12 bolt has taken some heat and gotten a bad rap from us torque arm guys. Its the craptastic torque arm mount the 12 bolt uses that causes all the failures not the 12 bolt internally. The load that the torque arm puts onto the nose of the carrier is... significant. In order to keep the stock torque arm location in place the 12 bolts use little tabs that you bolt into not through bolts like the 9" or Strange 12 bolt ( which break a LOT less but are usually noisy and build QC is iffy ) The S60 is a waste of time and hp IMO. Its a loaded carrier and takes waaaaaay too much hp to spin. The 9" is bad too. They both cost a lot of friction loss and really arent needed as I see it but there is nothing wrong with overkill so if breakages are your concern they are not bad options. That said they are not perfect either.... Theres been more than a few threads of S60 and 9" breakages too. Nothing lasts forever and abuse comes in many ways.

Hows the saying go? If your not breaking, your not racing

I just keep waiting the day someone breaks one of mine theres enough of em out there now. Boosted builds a plenty but so far nada one.

Mind you Im pretty much done with building them now. I get asked all the time but if I dont like the guy or the car isnt admirably worthy then no soup for you lol.

Small update my car is dyno ready but.... Theres snow on the ground today

Might wait until spring but it would be ncie to find out what that 6.2L is putting down.

To the OP? Dont put a 10 bolt in there your wasting time and effort.

BlueZee28

iTrader: (30)

I'm glad I got my 8.8 from you before you stopped making them

1ADan

iTrader: (4)

i had grabbed a 9bolt to toss in place of the 10 bolt drum setup that came in my TA. found a 9" on craigslist for $1000 and rid myself of the BW real quick. Rear's are a tough pill to swallow on these cars, but may as well do it right once. keep your eyes peeled for local deals, you never know when you might get lucky

cam-

Haha yeah well as I said for guys I like and cars I respect I step up. Most of the time I just dont have the time so Im not going to make time for something I cant get any pleasure out of either. One of the things that TRULY makes me happy is seeing vids of them getting BEAT on especially wheels up that makes my day. One of lifes little pleasures I guess just knowing that I can, not a money thing at all as there really is no money in building for sale or I would have production going full time but the satisfaction factor is high.

Plus I have this workaholic'itus so the odd time when Im actually caught up on work? Thats when I try and build some.

Anyways back to work here. Glad your enjoying it BlueZee

stoltz87

you guys are all a little hard on the 9 bolt.. i have one in my car and I've abused the hell out of it. i have a 320 hp 390 lb ft 357 ci small block with a 2500 rpm stall and it hasn't broken yet. i feel like those numbers are good for a street car and that rear end does fine with them

Pocket

iTrader: (24)

Early 3rd gen 10 bolts have a 7.5" ring gear. Later 3rd gens and all 4th gens used a 7.625" ring gear. Not much better
9 bolts use a 7.75" ring gear. While its a bit stronger than the 10 bolts, it is not even close to the common upgrade axles with over an inch more diameter

ghettocruiser

iTrader: (4)

I love my Strange 12-bolt. I replaced the crush sleeve/spacer with a solid spacer, and have beat the crud out of it. Of course Ive never done a clutch dump on sticky tires either. Maybe ill avoid that hahaha.

If I ever replace my rear, I will probably be going with an 8.8. I have extensive experience with them during my Jeep/offroading years. Ive geared over a dozen. Welded plenty of brackets and welded plenty of tubes. Im not sure if Ide trust myself to convert one to f-body bracketry and then trust it at the speeds our cars go.

But man, in a Jeep, with 38" tires, in 4-lo with god knows how much torque...they're just beasty. And the posi unit is easy to rebuild and tighten up. I built one for a Jeep XJ and it was great on the street and almost acted like a locker on the trails.

I got my 12-bolt with my donor car, and I factored that as about 1/3 the price of the donor. It was what sweetened the deal enough for me to jump when I really didnt have the money to do it.

J.