OK...What rear gears?

[coach]

Ok, I am getting ready to build a killer 8.5 for my GN build. I have an empty housing that I am going to narrow so I can fit my 15x10 rims in place. I am going 30 spline since thats our only option in an 8.5. I will use Strange axles and an Eaton Detroit Locker, but what gears? I know most run GM, but im not putting used gears into this rear. I do not have a set laying around and im leaving the original rear all together.
It will be a bullet proof as I can make it. Just need to know which gears to install. Im looking mid 600 rwhp, maybe more.

Thanks as always

 

[gusszgs]

If your talking brand, I run a set of Motives in my GS. It's an 8.5 10 bolt with a Eaton 30 spline carrier and Moser axles. Gears are wisper quiet, and so far so good

 

[TURBOPOWERED68]

i went with Yukon gears and have no complaints.

 

[coach]

Yes...brand. I'm using 3.42's.


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[coach]

This is the posi I am using in my new rear. Is anyone running this?
http://www.summitracing.com/parts/dtl-187c148a/overview/

 

[ttypewhite]

I have the same rear end you speak of with Eaton posi, Moser axles and Richmond 3.42 gears in it with C-clips. If your looking for something bullet proof, it's not going to be done with a Detroit locker in a 8.5 housing. The only way to get it done is with a spool and the biggest spline axles you can get in there, and brace the hell out of it. I have already spit out a ring gear when I was running high 9's with my old 109 setup and I have axle brace kit, Wolfe bar, LPW diff cover etc........

 

[JayC]

Id buy a 9 inch housing from Moser and fab it up yourself to bolt in like Currie used to do. Then you can put a good center section in it. I agree youre going to be hard pressed to keep anything in an 8.5 if youre making serious power without putting a spool in it. We went 9.05 @ 148 with a 8.5 and spool and it lived okay.

 

[83hurstguy]

AAM made the factory gears for GM. They are still available aftermarket if you do an Internet search. Had new AAMs put in mine two years ago, they work perfectly and are completely quiet.

 

[coach]

I have the same rear end you speak of with Eaton posi, Moser axles and Richmond 3.42 gears in it with C-clips. If your looking for something bullet proof, it's not going to be done with a Detroit locker in a 8.5 housing. The only way to get it done is with a spool and the biggest spline axles you can get in there, and brace the hell out of it. I have already spit out a ring gear when I was running high 9's with my old 109 setup and I have axle brace kit, Wolfe bar, LPW diff cover etc........

I understand where you and Jay are coming from. I would go 9 inch, but I really want to mod this "street" car using as many Buick related items as I can. I will brace the housing and I am going with the Ford bearing ends on the housing over C clip mod. This car has no cage, and is T tops. I have a transbrake, but dont really use it at the track. Its more fun for killer burnouts or making guys shit their pants at a stop light. I have designed bracing for the housing and will run the LPW Ultimate 8.5 cover with additional bracing. I also have the big forged yoke for the pinion. Im going this route for now, just to keep it all GM.

 

[T-CHRGD]

Id buy a 9 inch housing from Moser and fab it up yourself to bolt in like Currie used to do.

Currie still makes bolt-in 9" rears for G bodies.

 

[toofastforyou]

Donnie, I went with a Strange ''S 60'' Dana rear (part#PRSG10) with 35 spline axles and a spool. Gear ratio is 3:54

Claude.

 

[charlief1]

You could also do a 12 bolt which wouldn't weigh that much more than the 8.5 and would hold up fine. Donnie Wang went this route because it didn't cause binding issues in the rear suspension like the 9" has a habit of doing.

 

[coach]

I might make a set of 33 spline side gears and convert the 30 spline. If my guy can heat treat them like they need...cutting them is easy. I can't believe nobody makes a 33 for our cars.


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[novaderrik]

why are you narrowing the rear end? you can get the rims in there with the proper backspacing...

 

[coach]

why are you narrowing the rear end? you can get the rims in there with the proper backspacing...

Not the rims I have. I'm making the car fit the rims...not the rims fit the car.



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[forcefed3.8's]

I still have an 8.5/Eaton Posi/ 30 spline, c-clip eliminators. No issues yet. The ring gear is the weak link when using a trans brake.

 

[coach]

I still have an 8.5/Eaton Posi/ 30 spline, c-clip eliminators. No issues yet. The ring gear is the weak link when using a trans brake.

Way cool. 1019 horsepower on an 8.5!!! Now we'er talking. I think adding the Ford type ends will make it even better.
Thanks Rob


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[Nick Micale]

I might make a set of 33 spline side gears and convert the 30 spline. If my guy can heat treat them like they need...cutting them is easy. I can't believe nobody makes a 33 for our cars.
.......

I have 33 spline Moser axles in the 8.5" rear end of my race car which use the welded Ford ends?

The weak link in the 8.5" rear is the ring and pinion gears, and I have not found a race gear which is not as hard as the factory set which is made for long term wear durability, and is a "softer" gear that will absorb shock loads longer than the harder gears.

After trying many different makes of gears, I just replace the set frequently after trashing a few.

 

[NyBlankets]

This post was very helpful, thanks.