I was wondering how I can ID an 8.2 from a 8.5 without popping the rear cover off. Any ideas or experiences?

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I need GM style rear 1/4's for 70-72!! e-mail me.

8.2 has a 1 1/8 nut on the pinion,the 8.5 has an 1 1/4 nut on the pinion.

Look at the rear cover. The 8.5 will be perfectly round. The 8.2 will be slightly oval shaped. I found this in CHP magazine about five months ago.

The post about the covers is not true, the covers are identical. Bolt spacing is the same. The 8.2 cover and the 8.5 cover can be interchanged, no problems. There is no way to tell them apart by looking at the covers.

The sure way to tell is to pull the cover and look at the bolt holding the spider gear pin in. If it takes a 1/2" wrench to remove it, it's an 8.2. If it takes a 5/16" wrench to remove it, it's an 8.5.

Here's another tidbit I recently learned:
Look at the housing from the rear. An 8.5 will have two squared off chunks of casting hanging on each side near the bottom. An 8.2 will have a smooth bottom, same contour as the cover.

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70 & 1/2 RS Camaro
SB406 & M20 4spd
9" Rear
70 Malibu
SB350 & TH400

Gold Member # 103
Driveline Technician

Like I said, that was according to CHP magazine. They even showed pictures of the two. I'll find it so I can post the exact month of issue. Could it have been an Olds or Pontiac 8.5? Maybe, but CHP is usually a fairly reliable source of info. I'll check into it.

Found it. The 8.5 inch 10 bolt housing pictured in the May issue was installed in 70-76 Chevelles, 70-75 Novas, and 70-81 Camaros. Of course axle width and spring mounts will vary depending on application. But the cover pictured is perfectly round. It also shows the flanges at the bottom that Scooter reffered to. The thing that jumps out at me is the year models. It seems that most of the applications are mid seventies. Is there an earlier version of the 8.5 inch that used a housing with an oval cover? The consensus on this sight has been that the 8.5 carrier and gear will not fit into an 8.2 housing. The explanation given by CHP seems plausible enough. The 8.5 housing is slightly taller to accommodate the 8.5 ring gear, according to them.
Scooter, since you're in the business, I'd like to e-mail the pics to you as soon as I get a scanner set-up after the first of the year. Now I'm curious. I'd like to see if you recognize the housings. Could this be a major mistake on the part of CHP?

[This message has been edited by Randy Mosier (edited 12-21-1999).

[This message has been edited by Randy Mosier (edited 12-21-1999).]

It could be a mistake. I know for a fact the cover are identical, because we had to use an 8.5 cover on an 8.2 in a 72 El Camino one time. The 7.5 has the oval cover. I wonder if it's a typo on their part. I'd be interested to see the pics. Let me know.

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70 & 1/2 RS Camaro
SB406 & M20 4spd
9" Rear
70 Malibu
SB350 & TH400

Gold Member # 103
Driveline Technician

Randy:
The article in CHP Feb 2000 on page 42 has a listing of vehicles to get an 8.5 rear from. Nothing B4 1971 is listed. I don't recall any 8.5" rear to be available in 1970 on any Chevy. My 70 Camaro originally had an 8.2.

I'm starting to question CHP's facts because even this latest issue has some mistakes in it. See the post by DZAUTO under "Chevelle tech" about rearends and CHP.

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70 & 1/2 RS Camaro
SB406 & M20 4spd
9" Rear
70 Malibu
SB350 & TH400

Gold Member # 103
Driveline Technician

but,,, Will a 8.2 with a power trax locker hold up behind a healthy big block on street tires???? http://www.chevelles.com/forum/eek.gif

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Bob West
Monett,Mo.
1972 Malibu,461 cid.


[This message has been edited by Rapid Robert (edited 12-24-1999).]

An aquaintance I know re-builds rears as a sideline. He doesn't bother with the 8.2s. He sells to circle trackers, drag racers, and street machine folks like me. I don't have specifics, but thought it was interesting that he feels they aren't worth the time and money to fool with.
jmw

Helped a friend build a healthy big block for his Chevelle, and he had a 10 bolt in it.It was backed by an auto, and it outlasted the car, he totaled it after about a year.I have had both 10 bolts amd 12 bolts, and I have never had a problem with a 8.2 10 bolt. I might just be lucky though.

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1972 Malibu (1 st. car) Project waiting to happen
Team Chevelle # 427
A.C.E.S. # 1282

Scooter, I just got back home from a holiday road trip. I've got that issue but haven't opened it up yet. I'm still planning to send the pictures from the May issue for you to look over.