What parts to put in a rearend to hold up to 10's

[jetmech]

Im thinking of building up the rearend this winter. the car is not street driven much and will be putting a t-400 with a t-brake in soon. Should i go 30 spline axle with an eaton unit and c-clip elims. or (and im not to sure on the mechanilcals of these) a mini-spool (?) or a full spool. Now i would like some definition on the spools.Im going to keep the 8.5 rear
since i did alot of work to it sandblasting and painting it.

So what parts would you put in.
thanks Rich.

 

[Slow91z]

Some say stock replacement aftermarket axles are all you need.

I would go with either spool, makes it a pain to drive on the street at ALL.

All a Mini spool is is a solid piece that goes where the posi unti would be, and a full spool replaces the entire carrier.

 

[RobsIron]

Hey jetmech Do thread search and you'll find a lot of members that say a lot of good about the 8.5.

You can go 10s reliably on a modded 200r4 and a stock rear.

If you're gonna run slicks and race often...definately the axles and a rear cover with main cap supports.

While you're at it..throw on some rear discs.

 

[Dwayne]

You say that you are going to use a T-Brake. A stock diff. won't last long under that shock. I have had good results with a spool and 33 spline axles. I also had Ford ends welded to the rearend so I could get rid of the C-clips and I installed big Ford drum brakes on the rear. I have 1,000$ in the rearend including labor for the welding.

 

[Spooled85gn]

Just installed mini spool 2 weekends ago.. pretty damn simple.. Doesnt make it much of a bitch on the street.. Car went mid 12's and will go faster Saturday with the appropriate tuning we did hopefully.. All depends on how much $$ you want to spend.. At worst you put 10second power to it, whats going to break.. Axles? those can be replaced..

 

[turbodave231]

As a bare minimum, think about installing C-clip eliminators. If you've ever seen a car spit an axle, you wouldn't think twice about spending the money.

Lots of fast cars use stock 28 spline replacement axles from Moser with the c-clip eliminators. Spools are for race cars, and mini-spools won't hold up to the abuse of drag racing (and the manufacturers will tell you that).

The stock 8.5 axle is really quite strong and will take alot before it breaks. Using a T-brake on stock parts is a formula for disaster IMO.

Dave

 

[TurboCustomz]

You can definatly stay with the 28 spline stock replacement axles. Raymer went 9's in his turbo buick with the stock housing and 28 splines(i believe).

The only difference between the mini spool and the full spool, as stated above, is that the full spool comes with the carrier. Which is stronger and in most cases lighter. Both a plus.

I drove my monte on the street daily with a mini spool in her for over a year. It wasn't really that bad. Its hard on tires. I wouldnt really advise it, but it can be done. There's a lot of wheel hop in the turns and backing up SUCKS.

 

[chris718]

ive been in the 9s with a gn rear in my old ss monte carlo with a stock carrier and moser axles no c clip eliminators either.i do recommend them though.when someone comes in with your combo we install 30 spline axles ,with the matching 30 spline 8.5 carrier and usually a new ring and pinion even if its the same ratio so the t brake dont over excite the gears on a launch.a spool is only good for going straight so if you plan on beating up on some unsuspecting fords on the street just get a good auburn or eaton unit,the auburn is alot cheaper,rebuildable and works fine.i rememeber racing a mopar on the brooklyn/queens expressway and he broke a c clip.not a preety sight .the wheel and axle came out about 1 foot and then went back in.the clown in the car with me was telling me that the mopar guy had a stunt car and when i looked in the rear view mirror i saw what he was talking about

 

[jetmech]

Thanks for all the help guys, Im prob. going to go with 30 spline axles eaton posi, c-clip elems. and a new set of gears (3.42) thanks for all the help, .

PS. I thought the auburn wan NOT rebuildable and the eaton IS?

the auburn is alot cheaper,rebuildable

 

[Doug Jacobson]

When I did mine I got all my parts from Wayne at Gears AreUs He gave me a great deal on all the parts. I would recomend a spool actaully. I was kinda scared what it would be like in my car. It is fine the only time you notice the spool causing any trouble is backing up tight. The tires will skip a little. This is with a 28x10 slick and MT drag skinnies up front. The weight of the engine keeps the tires firmly planted and backing up with ease. I have 30 spline Moser axles, 30 spline spool and Strange C-clip eliminators. They have been in the car for over 3 years and no leaks or problems. I re-used the stock gears too, left the pinion in the rear when I set it up. It is a bit of a fabraction challenge to re-drill the mount flanges for the 4 bolt eliminators, plus you have to take off some of the material on the topside for the cross bar in the brakes to fit.

Any posi, even an Eaton will wear out quickly with Drag racing punishment. A spool is the sacrifice I made between rebuilding the posi every year or leaving it all together

I do 15-20 psi Trans Brake launches on it and haven't had a bit of trouble.

DJ

 

[d0n_3d]

I run 28 spline moser axles stock replacement and I still use C-clips and run high 1.5's sixty foots...no breakage here yet...i'm sure c-clip eliminators are recommended at my level

 

[turbo buicks]

anyone ever check out the true trac differentials? uses 2 helical cut gears, no clutches, etc. seems pretty bad ass

 

[Spooled85gn]

I really wanted to go with the POWERTRAX unit, but being that it was like 300 over what I payed for the mini spool in the car I said F#$K it.. But the powertrax unit seem to hold up to alot of power and still differentiate around turns and all..

 

[Slow91z]

I haven't heard any god things about Powertrax.

I to am curious about the true trac's...They look VERY strong.

 

[notched]

Auburns are a cone style rear and not very durable. GM tried using Auburns on the 7.5 equipt 85-88 G bodies as well as the 85-92 7.5 F bodies and the B bodies were using them until 1996. Onceyou slip them such as doing a burnout where one wheel grabs and the other spins, their days are numbered.
They can be disassembled BUT Auburn will not sell replacement parts for them. But they will rebuild a worn unit for a fee. Usually it isnt worth rebuilding. If you plan on sticking with the stock 8.5 then the stock clutch style carrier or an Eaton is the best way to go as both can be serviced easily by the average home mechanic. For max durability you can go with a spool.
I tend to not like splines higher than 30 on the 8.5 especially if using an Eaton or similar carrier as the carriers tend to crack at the saddles where the carrier bearings are pressed on.

 

[turbocliff]

Originally posted by Spooled85gn
At worst you put 10second power to it, whats going to break.. Axles? those can be replaced..

Do the new axles come with a new quarter panel and paint? So long as the car is being launched off the foot brake, I wouldn't worry too much about breaking axles, however once you add a trans brake into the equation (as jetmech is) it's a whole different story. I've seen GBodies loose quarters when snapping axles...

My current combo (bone stock suspension, no sway bar, & 90/10s up front, 29.5X9" Slicks) has yeilded 1.57-1.59 60' times, and with 28"X10" slicks, and the addition of rear air bags, I hope to go 1.53-1.55 off the foot brake. but once I go better than 1.50, you can bet that my next investment will be axles, c-clip eliminators, and either a spool or locker....

Cliff

 

[TurboCustomz]

As doug said above, You can get good prices from Wayne at Gears R Us. He's a local guy for me and he always does good work. Plus, he's a huge GN fan himself.
www.gearsrus.com