How long before Ill need to buy a bigger rear and how big should I look for
Im running a 383 carbed at about 480 flywheel do I need a 12 bolt?
its gonna be a street/autoX car
any suggestions or experiance. COST is a big deal!
any blown up a 7.5/8 horror stories on here?

 

Sticky tires is what kills them. Along with wheelhop/chatter. They live longer with an auto trans. I've seen them break on the street with stock LS1 engines on F1 stock tires.. I've also seen them last wheels up launches with slicks and 500+hp for hundreds of passes. Doing the mods to them helps no doubt but that's money that can be spent on a 12 bolt rear.. I picked up my used 12 bolt for $1200 I think. A rebuilt 10 bolt can run a good chunck of that. $100 support cover, $150 gears, $250 install, $25 fluid, $200-500 posi, $200 axles...

Goodluck! I went to a 12 bolt before breaking mine... Also.. selling a WORKING 10 bolt is easier than selling a blown up one.. haha

 

The first time that the tires hook up it will probably break. A Moser 12 bolt with a Truetrac would work well for auto cross.

 

All the improvements you can do to the 10 bolt still won't fix the size of the tiny teeth on the ring and pinion. Those will fail first. I pushed a beefed up 10 bolt into the 11's without it failing before finally upgrading to a 9",

 

Kinda glad to hear 11s on a 7.65". I wont be at the strip more than twice or so and never with slicks. Ill be befing it up via 28 spline axles, Eaton truerac, Alum diff cover, bearing spacer replacing the crush washer and ill be welding the tubes all the way around for about $900. If I could find a RTR moser 12bolt for close to that I would ****** it up but I think thats a stretch. Cash is a big concern because I have never accually ever seen the elusive green one.

 

its all in how you look at it. my 7.5 never gave me a fit behind my 383 with lots of dead hooks at the track. however i went with the safty of a 9". if i break an axle in that at least the wheel doesnt come off

 

I wouldnt put $900 into something that could break. I would save up and go for something bigger. IMO. As for me, Im a run it until it breaks kind of guy.

EDIT: Looks like the 8.8 swap wouldnt be easy for the fabrication challenged folks.

 

i have a 9bolt, had it about 12 years in a supercharged car, no problems, probbaly cost you $300 to get one.

 

Do the higher numerically gears help with the strength because its easier to turn the wheels?probly not im just thinking out loud.
Justin 87 GTA is a 9 bolt just another 7.5"?

 

no the ausi 9bolts are a little bigger and beefer. im not really sure wat cars they came in stock. 350 tpi cars maybe

and im thinking it would actully bea easier to break with say a 4.11 over a 3.73 cause its actully a torque multiplier

 

383 fbod. The austrailian 9 bolts came in cars from 83-92 i believe, but more common '88 or 89 to '92. Going from memory 12 years ago, the 10 bolt was like 7.625" but the 9 bolt was like 7.8" i think. They are good rears and come with 3.27's and 3.45's, you can get 3.70's for them. just go to a junkyard (if you can find any of our cars anymore) and count the bolts on the cover, then pop the cover and count the teeth on the gears and divide to see what gear ratio it is. i would definatley reccomend this rear, (good strength for the money). Don't pay more than $300 with brakes, you may get lucky and get it for less. u will be happy with it. they dont break...(unless like any rear you sit there in a parking lot doing donuts all day)

 

You WILL have to upgrade the rear end. Best not to throw good money after bad, I'd just nurse the poor 10 bolt along and save up the money for a 12 bolt, Dana 60 or 9".

Dan

 

I broke about 4 chunks of teeth off the pinion gear last week, (7.5 ten bolt) i have a 91 stock 350 tpi with a procharger. and street tires. new gears under warrenty on their way.. saving for Moser 9 in