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10 bolt posi units

3K views 15 replies 12 participants last post by  HwyStarJoe 
#1 ·
I have a 68 camaro with a 10 bolt rear end it has a an 8.2 ring gear with 28 spline axles. will the 8.5 posi with 28 spline axles fit in the housing? I want to replace the diff with a posi unit and it seems the 8.5 posi are more readily available than the 8.2. Will any 8.5 posi unit fit?

Any ideas out there.
 
#4 ·
Sorry, you can't put an 8.5 diff in an 8.2 housing. If you want the 8.5 your best bet is to find a '70's Nova rear and bolt it under your '68. I'm running an 8.2 with an Eaton posi, but I'm not doing six grand holeshots with slicks on. I am definitely considering the Nova swap because the 8.2's are weak. If you stick with the 28 spline axles your 8.2 axles will fit in the Nova rear.

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'69 RS Camaro
355 5-speed 4.11
 
#5 ·
you can also re-use your brakes and differential cover on an 8.5 rear. I know, because i did. wanna get sneaky and tell people the 8.5 is the stock 8.2? grind off the "ears" on the bottom of the pumpkin to make it look like the stock 8.2 does. don't know why you would need to do that, but if it HAS to look original...

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1971 Nova(looks like 69 camaro from underneath!)
355sb, vortec heads, HOT cam,T-10 tranny, 3.70 gears 16X8" IROC wheels. 12" Corvette brakes on the way.
see pics here http://community.webshots.com/user/novaderrik

[This message has been edited by novaderrik (edited 11-02-2002).]
 
#6 ·
Well actually you can run an 8.5" carrier in a 8.2" housing...it has been done. Its kinda a pain-in-the-___, because you have to change the bearing configuration and clearence some parts of the housing. But IMHO its not worth the trouble. I have done this for guys that HAVE to run the factory housing (in some forms of racing) before EATON (thankfully) started producing new units for the 8.2.

I'd do what 1 2RUN stated, find a 70's Nova 8.5" rearend or find a 12 bolt.
 
#7 ·
The 8.5 from a '72-'74 Nova, Omega, Apolo or Ventura is a bolt in. This is the way to go if you don't have the bucks for a 12 bolt. If you want to build the 8.5 later you can upgrade it to 30 spline axles with a 30 spline Eaton posi and Moser axles, or 12 bolt Camaro axles. There are also some other upgrades available for it. I have had good results from the new Eaton posi for the 8.2. It is stronger than the original 8.2 posi and much better than the Auburn.

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'69 RS/SS396 pro street
427/4spd/9"
Byars Performance
High Performance Drive Train Parts And Service
www.lubedealer.com/biggearhead
 
#8 ·
Not to take this thread a different direction, but I am about to rebuild my 10 bolt '68 rear - the big question is Eaton vs. Auburn. Locals here all say Auburn, but everything on this site says Eaton. What are the big differences. ($$ are not as important as buying the "right" unit). Thanks.
 
#9 ·
Eaton, Eaton, Eaton. The Eaton is a far better posi. It works better and is rebuildable. The Auburn will fill your rear end with powdered metal as it wears.

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'69 RS/SS396 pro street
427/4spd/9"
Byars Performance
High Performance Drive Train Parts And Service
www.lubedealer.com/biggearhead
 
#10 ·
Freddie,

I've been meaning to ask this for a while and this is the best thread to ask it...
What's the advantage of swapping 30-spline axles as opposed to 28 in an 8.2" rear? Or can I only go to 30-splines in an 8.5"?
I've been turning that question over in my head for a while and I'm wondering what the TECHNICAL answer is.

Tnanks!

------------------
Joe
WCA Member
1969 Wallet Crusher
- HwyStar@Rochester.rr.com

HwyStar's Garage!

[This message has been edited by HwyStarJoe (edited 11-04-2002).]
 
#11 ·
While we're on the subject here, just wondering if any of you have had any experience with the Powertrax system from Richmond Gear. For those people who are OK with their gear ratio and don't want to mess with the ring gear and pinion, this seems like a very attractive application for getting posi. Whos tried one and what's your opinion?
 
#12 ·
Freddie is right on about the Eaton. I've used the Auburn in my 8.2" and burned one up after 1.5 years. It only cost me $90 to replace the Auburn with a new Auburn (DREX program) but I still had to clean all that crap out of the differential housing.
 
#13 ·
30 splines are stronger than 28 that is the advantage.

The Powertrax locker works fine and is easy to install. They do make a lot of noise (snapping, banging, popping and clicking). Make sure you install it as the instructions state. I used the "track" locking springs (not the street springs) in my rear end and haven't had a problem in the 1 1/2 years it's been in the car. It's seen high 11 second passes with no problem. I have heard of a few people having problems, but I think if the unit is installed correctly they are very good (except the noise), I would not want one in a daily driver due to noise and the way they make the car handle (an absolute NO NO in rainy conditions). My car does see a 99% street duty but only in good weather and is not my daily transportation.

Royce
 
#14 ·
I got the new version Eaton 8.2 from Freddie and it works great. I've had it close to a year now. I don't thrash on it a lot but when I do it turns both tires like they were welded together. No noise what so ever when making a turn.

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Robert Johnson

'69 getting better every day... (every pay day)
350ci 700r4 3.55 posi A/C PS PDB
 
#15 ·
Stock 30 spline axles are about 30% stronger than the 28 spline axles. Moser axles are about 30% stronger than stock. If you go to 30 spline Moser axles then they are about 60% stronger than stock 28 spline axles. Sound about right? I don't know of a way to put the 30 spline axles in a 8.2, but putting them in a 8.5 is easy.

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'69 RS/SS396 pro street
427/4spd/9"
Byars Performance
High Performance Drive Train Parts And Service
www.lubedealer.com/biggearhead
 
#16 ·
Ah, OK... I thought it had something to do with the spline count. No wonder I couldn't figure it out.
Once the snow melts and the ground thaws in 6 or 7 months, I'll be out digging around for an 8.5" to put together.

Thanks everyone... again!

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Joe
WCA Member
1969 Wallet Crusher
- HwyStar@Rochester.rr.com

HwyStar's Garage!
 
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