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In my 64 Nova drag car I have this rearend. I was told it was an Olds from the seller I got it from who did not build the car. I am far from an expert but I thought all GM's rearends had a bolt pattern on the back like 10 bolt 12 bolt. And ford were this type. Any insight or ID of this would be very helpful. I can take a pic if the other side if need be. I just had these pics on file already.

It does have a 6 bolt pattern to bolt the wheels on. Was also told it had commercial axles. Has anyone heard of Commercial axles? Or what does Commercial mean? Thanks for your time.







 

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Does the front look like this? According to the article:

Pontiac and Oldsmobile shared this Hotchkiss-type axle from 1957 through 1964. With its massive 9.30-inch ring gear and optional Eaton limited-slip differential, it was the third member of choice in the heyday of the supercharged Gasser and was as popular among racers as the Ford 9-inch. But that was nearly 35 years ago. Today, service parts are scarce, though ratios from 4.10 to 4.88:1 are still available. Thanks to its mass, this axle can safely handle 400 horsepower. The best cases have three stiffening ribs (shown), and the ’57 housing is a direct bolt-in for ’55-’57 Chevys.

http://www.hotrod.com/techarticles/axle_rear_end_guide/
 

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Commercial axles means pickup truck axles. Only the pickups trucks from GM had the 6-bolt pattern during the 50s-60s-70s.
In the old days Chevrolet cars had the 6-bolt pattern through 1948, although there were a couple in the mid-30s that had 5-bolt. The trucks continued with the 6-bolt after the cars changed to 5-bolt.
 

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Photos you show are of the wrong side ... ;)
Early Pontiac and Oldsmobiles did indeed have a rear end without the bolts and cover on the rear. They look a good bit like a 9 inch Ford. 55 to 64 Chevrolets also has a the " pumpkin style " rear end like in your photos.

Show us the front side of the rear end.



This is a 9 inch Ford center section ... sometimes called a " pumpkin " by some. Look at the studs shown by BLUE arrows ...
IF you can use a deep wall socket on these ... it is a 8 inch Ford ... if you have to use a wrench ... it a 9 inch Ford .



Here's a aluminum after market one.
 

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That pic of the backside of the housing could be either the GM or Ford axle.

The removeable front is "somewhat" similarly designed for both makes of axle, BUT the pinion shaft and bearing can be removed by unbolting the front section of the Ford axle center section only, the GM axles have the same style of mounting the pinion shaft as the later model axles still do.

The only GM axle that has a similar removeable pinion shaft retainer like the Ford axles had, are the truck only 14-bolt. There may be another or two but they are still truck only axles.
 

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My vote is for Olds/Pont. Reason, the 9 inch has a flat spot on the top and bottom of the housing. The OP is round. The 6 lug axles have me stumped though.
 

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When you're welding stuff together you can make about anything. My old Don Clar digger had an 8.75" Mopar center section with Olds ends and Edsel brakes.
 

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Discussion Starter #10
I will post some more pics tonight when I get home from work.

Thanks for all the help.

George
 

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UPDATED PHOTOS

Sorry it took me a few days to get back with pics. My car was getting some exhaust work done.

Here is some pics or the front of the rearend. Again I was told it was an Olds. From what I can tell it does not look like any of the above pics that were posted. It looks longer on the shaft end. And also like you could mount something on top of the shaft part. But then again I know nothing about rearends. My dad said the calipers on this rearend are very larger than normal.

So anyone take a guess? It would be nice to know what I have. I did do an tire spin test and drive line went around 4.5 times to one tire rotation. As always thanks Hotrodders.

George







 

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That's a Mopar center section. Mopars have the pads for the pinion snubber. On the lower driver's side there is a casting number to help you identify it.
 

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YAh it looking that way from this site that above member posted.

http://www.hotrod.com/techarticles/axle_rear_end_guide/index3.html

Mopar 8-¾

Produced from 1957 to 1975, the 8-¾ is very rugged in stock form and actually surpasses a stock Ford 9-inch in the brute strength category. It carries 30-spline axles that are stronger than the 9-inch 28-spline units, and the stock upper pinion bearing carries the same service part number as the upgrade Ford Daytona pinion bearing (HM89443). The best cases for this sleeper bargain are identified by numbers cast into the driver side (arrow); 742 identifies pre-’68 units, and 489 appears from mid-’68-up. When it comes to limited-slip diffs, the 742 employed an excellent Dana Powr-Lok clutch-type differential, but the 489 cases used an Auburn cone-type limited slip (the only caveat here is that the unit cannot be rebuilt). Either case can handle more than 500 hp in stock form and as much as 700 with aftermarket 35-spline axles. Stay away from cases marked 741; they have an 8¼-inch ring gear and weak 13/8-inch pinion stem. Beware of pre-’65 axle shafts with press-fit brake drums; service is a nightmare.



The good thing is they say it is strong one if I got the right casting number. Not sure what to think about having Mopar rearend in my Chev.
 

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The good thing is they say it is strong one if I got the right casting number. Not sure what to think about having Mopar rearend in my Chev.

It beats the stock 8.2 rear in strength and serviceability. When you're cutting down a rear end for a race car you're not too concerned about whose name is on it, just how well it will perform. I'll bet you don't have a lot of GM parts on the engine, the interior isn't original GM, so the rear axle looks right at home.
 

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what rearend

It looks alot like the '58 Pontiac rear we ran in our TF digger. It was plenty stout, would handle 2,000 horses, no problem.
If you aren't having problems with it, I'd leave well enough alone. If you are, a Ford 9" is going to be easier to get parts and brakes for. Mike
 

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FYI

NO Ford 9 inch housing ever had a perfectly round backside. If you look carefully they are all slightly egg shaped.

So, when you see a perfectly round one...... it probably is a Mopar, or less likely a BOP.
 
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