I am running a 1989 camaro iroc with a 383 stroker. The motor is putting around 400 hp to the rear wheels. I am trying to figure out what to do with the rearend and i figured you guys could throw some of your ideas that you have used on your projects my way. Any help is much appreciated

Thanks
1fastrock

 

I do not have much experience in rear ends but I do know I will be using a set of Richmonds' Competition 3.89's (lighter than their other gears) [Edit: Richmond no longer offers 3.89's] (Looking into 3.73's or possibly 4.11's) to help with Drifting my IROC. I just need to find some 28 spline axles for the swap as well as an LSD that can take the punishment of drifting and I'll be ready to go. Also this car will still be a street car, and still driven on the freeway.

Hope you find what you need.

 

How much traction do you think you will have? If you keep street tires on it and they don't hook up then you can probably upgrade the stock 10 bolt and be all right. I'd run an Eaton Posi with 28 spline axles and Timken bearings. Be sure that the gears are set up correctly.

If traction will be good then you are going to need something stronger. A Moser 12 bolt is a very good choice, but not cheap. They start at $2200 plus shipping. You won't have to ever worry about breaking it.

For the drifting car, I'd recommend a locker of some kind. A clutch type differential like the Eaton or Auburn will not hold up to that kind of driving. The clutches will eventually start slipping and then they will overheat and go out. A spool would be all right if it was never driven on the street, but you want to keep this car on the street too, so count out the spool. A Power Trax Lock Right would work well on the street and drifting. It will lock up 100% when drifting but still unlock when making turns on the street.

 

What's it have now? The 9 bolt will take that as long as it's in good shape (cones not worn too far).

 

It is the stock 89 camaro rearend. I think it is a 10 bolt with an 8.5 ring gear but i could be wrong.

 

It has a 7.625" RG.

 

i have a moser 9". work just fine.

 

my stock 87 9bolt behind my stock 350tpi and 86 TA 305 TPI 9bolts are both pretty shot, one wheel peel. they have a 130,000 on them but they are a good choice. im gona have a 383 HSR putting close to 400rwhp as well. and that will grenade a 9bolt/10bolt... maybe not at first but its life is limited. depends on traction and how its driven. u can upgrade the stock 10bolt to handle about 400rwhp with a eaton posi/locker, 28 spline moser axels, really good bearings, a support cover etc and of course they have to be setup really well. but again.... wont expect it to last too long but it will hold up. its the small ring/pinion thats the weak link. the 9bolts are stronger but there are no performance parts for them.

im building a ford 8.8 to go behind my 383 HSR... rebuilding the posi with carbon fiber clutch packs, 28 spline axels and 3.55 gears. (trick is u gotta fab up a custom TQ arm mount) should be almost as strong as a 12bolt, woulda been stronger than the 12bolt if i used 31 spline axles.

cost me, 50$ for used posi and 3.55 gears. 100$ for the carbon fiber clutch rebuild, 8$ for new ford racing ring gear bolts. just need a housing with disk brakes, prob 200$ and im set. if i need new axles for the chevy bolt pattern then 300$ from moser or can i redrill the stock 28splines for the chevy bolt pattern?

so in a nut shell u can rebuild a 10bolt to handle it but ur looking at about 1000$ before gears/installation etc. 400-500$ posi, 300$ axels, fluid, 110$ support cover, new bearings/seals etc...

or find a 9bolt and work with it... could cost 400$ for the posi new... or get a cone rebuild kit. 110$ for the support cover, fluid.bearings, gears etc

or throw 2400-2900 at a moser 12bolt/9inch

 

Is there anywhere i can get complete instructions on how to do that swap properly?

 

which swap?

 

[quote=big gear head;4162911]

If traction will be good then you are going to need something stronger. A Moser 12 bolt is a very good choice, but not cheap. They start at $2200 plus shipping. You won't have to ever worry about breaking it.

quote]

I'm still flogging my old 10 bolt but I don't have near the power that you do. If you can afford the $$ 12 bolt is the way to go.

Dan

 

I pushed a 9 bolt into the high 11's with 3.27 gears. I swapped in a beefed up 10 bolt to get a deeper gear ratio and pushed it into the low 11's before installing a 9" because I installed a tranny with a transbrake at the same time as the diff.

No matter what you do to the 10 bolt, it will still have the tiny ring and pinion and that will always be the weakest part of the diff.

Your 89 IROC "may" have a 9 bolt. Get under the back of the car and count the bolts on the cover. A 10 bolt will also have a smooth cover and a 9 bolt will have a rubber fill plug in the cover.

 

I'm running a nine bolt with a TA cover for added strength. I'm currently at 370+rwhp. This is also an A4 car. If you are running a manual transmission than you may be pushing things depending on your traction.

 

Sorry buddy you most likely have the the GM 9 bolt in your IROC as in my GTA it is strong but you are limited to the stock cone type LSD or an expensive German clutch type LSD. Assuming yours is not worn out you can get gears for it you may have to search for a while. If you do have a 10 bolt, might be in a 305 IROC, then get a TrueTrac best way to go bar none. If you go to another rear best deal I have seen is a Currie 9 inch for around $1300 bucks that will bolt in. You will have Ford explorer rear discos to live with.

 

What diff are you running in there? The stock LSD?

 

What diff truetrac?

 

Stock.

 

the 9bolts arent weak. they are something like 25-50% stronger than the 10bolts bc the 9bolt has larger carrier/planitery lol(something along those lines ) also the axel caps are closer together which increases strength... only prob is that the ring an pinon altho larger than the 10bolt (7.5") vs 9bolt (7.65) is still really weak even compared to the 8.5" 10bolt and 12bolt/ford 8.8 etc. again the 9bolts had 28spline axels stock but your limited to stock LSD/posi and axels etc. stock the 9bolt is rated to like 295hp and 340ftlbs tq i believe. so if u decide to push it then its really just hit or miss if it will explode.

10bolts are easier to find and cheaper to build and have alot more aftermarket help. i was in englishtown NJ like a month or so ago for a car swap/show... there were 4 4thgen 10bolts with disks for sale at about 200-275$. and a couple 3rd gens with PBR brakes.

get the 9bolt if its in good shape, but i would rebuild the posi just for insurance, and get a support gurdle. but they are harder to find. or get a 10bolt and beef it up alot. if u got some money to throw around get the 12bolt... hands down and call it a day