[BuddyP]

How can I tell the difference between these 2 (other than ring gear diameter)? Or do they use the same housing? What are the part code differences?

Thanks
Buddy P

[pdq67]

An 8.2 has a 10 bolt cover on it that looks like a 12 bolt's "12 bolt" type cover whereas, I think the 8.5" rearend has tw lugs that hang off the lower right and left sides of the bottom of the center casting so that you can tell them apart quite easily if not mistaken from the lower back of the cars....

pdq67

[DOUG G]

http://www.novaresource.org/axle.htm
This has a picture of what they look like and some of the differences.

[boodlefoof]

If I remember correctly, the 8.5'' unit also uses a higher spline count on the axles which contributes to making them a bit stronger.

[HwyStarJoe]

The 8.2 10-bolt has a 1 1/8" pinion nut and 3/8" ring gear bolts with 9/16" heads.

The 8.5 10-bolt has a 1 1/4" pinion nut and 7/16" ring gear bolts with 3/4" heads and left hand threads.

[BuddyP]

So if I were to get a Posi differential for a 10 bolt, do I want the 8.5 housing or doesn't it matter? Kinda limited on knowledge on rear ends. A full differential housing replaces the ring and pinion gears right?

[HwyStarJoe]

The carriers are different between the 8.2 and the 8.5 rears. You can't use an 8.2 carrier inside an 8.5 rear end, and vice versa.

[BuddyP]

Are the leaf spring perches something you can buy to weld on? Have a chance to get a 8.5 10 bolt but the leaf spring perches have been cut off.

[WildBillyT]

Moser makes a nice set for around $70.

[novaderrik]

i got a set of "Mopar" spring perches from a circle track supplier for $15 when i put the 8.5 in place of the 8.2 in my nova. i only needed them because the housing was setup for multi leaf and my car had mono leafs at the time.
i re-used the 8.2 axles, brakes, and rear cover and put a posi from a 79 Z/28 with Richmond 3.70 gears (bought both together for $100) in a housing i bought out of a 74 Nova in the boneyard for $50. another $40 to get the perches welded on and $50 to have my cousin's friend set it all up. another $15 in Amsoil series 2000 gear oil and i was set.
but i got off really cheap, and it worked pretty well for 4 years until i traded the car off last fall.

[BuddyP]

What do you mean "until" you traded the car off? What kind of power were you putting out with your car? A buddy of mine can get a locking differential for nothing.

Are these holding power pretty decent? 500hp range? Should I just focus on a 12 bolt? Just had a lead on a 8.5 10 bolt is all.

Also, I've heard that the 8.5's out of the Nova's will bolt right up to the 1st gen camaro's, is this true?

[HwyStarJoe]

8.5's out of Nova/Apollo/Omega bolt right in. They're the same dimensions as the First Gen rear ends. No fabrication required at all.

If you're throwing 500hp at the rear wheels, I'd go with a rebuilt 12-bolt. But everything I hear says an 8.5 that's rebuilt properly with higher spline axles like Mosers and a quality carrier and gears is still less expensive and just as strong as a 12-bolt.
If you already have the 8.5, go for it.

[BuddyP]

I don't have an 8.5 currently but I would be putting in a good set of 30 spline axles

[camaroman7d]

The 8.5" rear end can be built very strong. If you want to run 30 spline axles you will of course need a carrier that has 30 splines as well. Stock is 28 spline. If you get 28 spline aftermarket axles they will be much stronger than stock. The ring gear is larger on the 8.5 vs. the 8.2.

I built my 8.5" with Moser axles (28 spline), ARP cap studs, c-clip eliminators, locker, and aluminum support cover. Ran in the 11's for years and never hurt it. Built a blown small block didn't change the rear end and still never hurt it. It is still in the car and the guy I sold it to put in a blown engine as well. My point it they will take a lot of abuse if built right. Even in stock form they are pretty darn strong. If you are going to run slicks and a trans brake you might want larger axles. If not I doubt you would hurt the 28 spline axles. You didn't say how much power or how fast you are trying to go so it's hard to make suggestions.

[BuddyP]

Yes I would be getting a 30 spline carrier and would get HD 30 spline axles. I am building more of a Pro Touring car so would not have slicks or be making hard launches, and will probably not have more than 500hp.

Are the 30 spline axles between the 10 bolt and 12 bolt the same? (interchangable?)