Is it just me or are yall sick and tired of the 30 year old bs flying around about trannys and 12 bolts and ford 9's? I read but have not witnessed that cars are running bigblock juice motors on properly set up 700r4's and 10 bolts. Times are tough and some of us have to do more with less cash and I'd sure like the straight truth about running race preped stock running gear in my 88 2.8 auto thats getting a pretty stout 355 motor swapped in soon.

 

10 bolts will last to a point. Race prepped 10 bolts dont exsist. You can build a 10 bolt but soon as you put on slicks and hook and start dipping into the 10-11 second range kiss the rearend good bye. I have $1000 worth of crap thrown at my rear end and I know slicks will be the death of it if I ever slapped some on.

 

The reason that you hear all of that stuff is because they work. Go ahead and use your 7.5 10 bolt and you will see why guys use the 12 bolt and 9 inch, along with the Dana 60, 8 3/4 and a few others. The 7.5 is a piece of economy crap that should have never been used in the Camaro. Even the Mustang got the 8.8, so those guys have something to work with.

 

been 9.72 at 142 on a 1.49 60 foot on my bone stock junkyard 4th gen 10 bolt rear witih 2.73 gear

been 1.41 and 1.45 60 foots running 10.6 and 10.7 at over 126 mph on a nitrous motor with another stock 10 bolt 3.42 rear from a 4th gen.

87 TA has been 1.38 on a LOW 10.0 at over 133 mph nitrous 406 on a stock 10 bolt 3.73 rear...

Maybe we are just lucky but I've done many 10 second passes on a 10 bolt, however I dont use a trans brake and just leave off foot brake. Most 60's are in the 1.5-1.6 range nowadays.

My 11 second n/a 383 ran 1.5's all the time...had dozen passes on that setup i guess and probably 5 passes plus 3 dyno pulls and countless street roll ons on the turbo motor before i chipped a worm gear inthe posi. Went to the 2.73 rear and have maybe 8 passes or so on that rear.


I wont go to a 2500 dollar rear end til I start braking these 100 dollar rears and so far I havent. May need to do so if I ever get a transbrake but I'll try it first before changing rears

 

There are always exceptions. There are also many people who have broke these 7.5 rear ends on the street with street tires. You just never know.

 

As said above, you hear about them because they work when stock doesnt. If you are on a budget that is all the more reason to either build the entire driveline to handle the motor, or dont build so much motor. If you dont have much money now, what are you going to do when you blow the axle up or fry the clutches in the trans? Do it once, do it right.



My brother use to own the Camaro that I have now. When he had it he broke 4 teeth off the pinion gear on the street on street tires.

I bought a 9" so I dont have to worry about it. Also because I know when parts fail they usually do so at the worst time. That for me would be when I'm at the track (which I drive to) that is 20 miles away from home.

 

To be honest, I think the street on street tires is how I broke off a tooth on the worm gear... getting sideways spinning tires at 50 mph rolls and then letting off to instantly hook back up kills posi rears i guess. Constant locking up and disengaging.

I did crack a spyder gear in my 9 bolt rear end with a mild bolt on L98 doing 1.7 60 foots. Some hold some dont.

 

hmmm take what you can use and leave the restis my motto, we have a real good argument here for both sides but the ***** gettin deep, no such thing as a race prepped 10 bolt? and you know your 1000 dollar rear will spray with slicks? i guess ill be my stubborn self and prove ya wrong just because, theres more to parts and "race prep" than all the hot rod magizines and ford 9" hype these journalists have been cramming down our throats forever

 

Ok. You have fun. Do you know what the weak part of the axle is? Its the size of the gear. There is nothing you can do about that. You can make it stronger than stock, but its still not that strong. What exactly do you plan on doing to "race prep" the little thing? Was there really a point to this thread anyway?

Are you saying my $1000 (I wish it was only $1000) rear end will break on slicks?

 

I said my $1000 rear will break on slicks. And I have the best of everything in it.

 

Why even post if your just gonna do stuff the wrong way any way. You can try and build a 7.5 like a brick **** house but the fact that still remains is the crappy little ring gear. You might build a rear and it will last 50 passes and then again it might grenade the first pass. Flip the coin and test your lucky cause thats all you have drag racing with a 10 bolt.

 

Even a 9" isn't indestructible. I caught mine just before it failed and I was running mid 9's with it with a stock C7AW-E case.

As mentioned above, you can add all the beef up goodies to the tiny 10 bolt but it doesn't make it much stronger. There's more to a diff's strength than just the size of the ring gear. The whole 7.5" diff's design is weak. Unless you're going soft launches like Orr89RocZ, it will fail.

I ran a beefed up 10 bolt into the low 11's before switching to a 9" because I installed a transbrake at the same time. I didn't think the 10 bolt would have lasted long doing transbrake launches.

You can run a 10 bolt if you want and keep putting money into it if it fails but eventually, you'll spend enough on the 10 bolt that could have bought a much stronger aftermarket diff. Just to beef up the 10 bolt, you should be spending around $1000.

 

Just my 2 cents, but isn't the 10bolt the reason GM put a 9bolt in the Camaro's and Firebird's when they went to the 350?

 

Not all 350's had the 9 bolt. For instance, my 91 L98 camaro came with a 10 bolt and my brothers Q-jet 85 305 came with a 9 bolt.

 

From everthing i have read and seen, the L98 was to come with the G92 package which was a 9bolt with the AT. But then I have been wrong before?

 

hey now, i wouldnt call some 1.4's very soft But your right, 1.5x to mostly 1.60's arent much of a 60 foot so the 10 bolt can hold that in an auto car on the footbrake.

Trick is to run short tire and lower numerically gears like 3.23-3.42's. They have thicker gears than the bigger 3.73's 4.10's etc.

transbrake or stickshift i'd be careful with....

 

From '90-'92 the 9-bolt was not used. They all got the 7-5/8" 10 bolt.

RBob.

 

Some early 10 bolts were 26 spline axles while the later ones were 28 which are suppose to be stronger...but 90% of the time its ring gear or posi case that breaks first.

 

Note that there is another GM 10-bolt rear diff that is much stronger then the 3rd gen 10-bolt diff.

That is the earlier corporate 10-bolt. With a 8.5" ring gear. Only 1/8" smaller then the 12-bolt ring gear. It is much stronger then the 3rd gen 10-bolt.

So, the issue is, when someone states "it's a 10-bolt", which one is really under the car?

RBob.

 

The 8.5 is 3/8 smaller than the 12 bolt. The 8.5 is a very good rear end, but GM didn't see fit to install it in the 3rd and 4th gen F body.

 

You are correct, 8.5" vs. 8.875" for the 12-bolt. That's what I get for posting late at night

It would have been great to have had the corporate 10-bolt under the 3rd/4th-gen f-bodys. Although, IIRC, wasn't there a Dana rear that could be purchased via GM performance parts or such?

RBob.

 

Let me ask a silly question, why is it that the ring gear breaks? Is it because the ring gear is inherently weak? or is it because of flex in the axle housing or tubes? If this thing really is a piece of crap then what might be a decent truck axle from a boneyard that would be a worthy upgrade with disc brakes maybe? I can fabricate and weld and my goal is to get a 10" slick under the car without a total backhalf and have it live. I wonder if a gusset to reduce flex and quality gears and good setup might work.

 

You can put any rear end under it that you want if you use ladder bars, 4 link or some other type of after market suspension. It's much harder to use the stock torque arm suspension. The '99 and later 8.6 truck 10 bolt is a good rear end to use. It's very similar to the 8.5, but it has larger differential bearings and the ring gear diameter has been increased by 1/16 inch. They also use 30 spline axles, but that won't matter much to you because you will have to replace everything inside it anyway.

There is also the 8.8 Ford, which is a very good rear end. Again, you would only be using the housing and putting everything in it new.

 

Flexing definately has something to do with it but its just that there is not alot of material there and the stress the pinion teeth and gear teeth have to go through just shears them apart sometimes. But flexing of the casing can offset the contact pattern and really concentrate alot of stress on a smaller area of the tooth and thus the parts break.

If there was a way to make the ring gears out of a extremely strong material, and then use welded axle tubes and differential girdle for support, i think 10 bolts would last alot longer and possibly never fail under most street/strip applications.