1970 Skylark differential ID

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1970GS
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1970 Skylark differential ID

Post by 1970GS »

New to me '70 Skylark Custom, 455, not original. There is a witness mark on the pass tube that looks like the s/n has been ground off! Nothing on the driver side tube that I can find.

The center section has cast # B027 and 9783393 on the driver side rear and clock cast on the pass side. it also has the scalloped inspection cover, strap U-joint and ribs on the side and running from the suspension bracket on top to the front, see the photos.

Also, rotating the tire/shaft, one full turn of the tire it is just short of 4 turns on the U-joint, I assume a 3.91 gear. Both tires turn the same direction, so also assume posi.

Can anyone tell me what rear this is, 8.2, 8.5, possibly a Pontiac? If necessary I can pull the cover and provide additional photos.

Thanks, Larry
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1970GS
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Re: 1970 Skylark differential ID

Post by 1970GS »

More photos. This car is a GSX Clone, appears to have suspension upgrades, very hard shifting modified TH-350 that will squawk the tires 2nd and third. Not that I do that sort of thing... :shock:
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monzaz
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Re: 1970 Skylark differential ID

Post by monzaz »

[attachment=0]Pontiac 10 bolt 8.2 axle suffix code location. You have a 10 bolt 8.2 PONTIAC rear under your GS.... NOT Original to your 1970 Buick...WHICH might be a good thing...lol.

The appeared to be grind mark is a NORMAL occurrence on rear end tubing. Chevy, Pontiac, Olds 12 or 10 bolt ...There were some flaws in the tubing and that is just the way they were.... We see that a lot on camaro rears. It has nothing to do with someone grinding off numbers etc. they are not in consist spots of the tubing ...just random...

More info on the rear under the car.
YOUR Pontiac rear will have its code on the driver side tube back side (facing the back of the car level with the ground)
The casting is a B 02 7 (February 2nd 1967 rear end)

You can buy parts for this rear fairly reasonable prices and find good gear ratios also. We have all the parts in stock to change out your gears etc.

FIND that axle suffix 2 letter code ont he driverside tube (back side between the spring perch and cast center) ON THE STEEL AXLE TUBE...
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Pontiac 10 bolt 8.2 axle suffix code location.jpg
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1970GS
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Re: 1970 Skylark differential ID

Post by 1970GS »

Thanks for the info, I assume there are more codes I should keep looking for, I can almost "make myself see" a faint H on the rear of the drivers side tube, I'll do more cleaning soon.

I appreciate the help. Why do you think it might be a good thing? Parts availability? I've had two 1965 GTO's, this might be the same rear they had. I tore one up, spider gears, the other I beat on hard, it held up.
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monzaz
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Re: 1970 Skylark differential ID

Post by monzaz »

YEs, PARTS are real expensive for the 68-70 Buick rears. THAT is not to say they will not hold...Just ease of parts and prices. :) Jim
J D Race
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