Author Topic: 12 bolt width/8.5 10 bolt posi questions  (Read 2559 times)

69Z28

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12 bolt width/8.5 10 bolt posi questions
« on: March 23, 2008, 11:01:37 PM »
How wide is the Camaro 12 bolt backing plate to backing plate? I measured mine at approximately 53". Is this correct?

Also, I have a 8.5 10 bolt posi that measures approximately 56" backing plate to backing plate. Could this be for Chevelle possibly? Or 70's Camaro? I have this coil spring 8.5 10 bolt with a traction lock posi (based on info I received from BIGGEARHEAD last year) that I have no idea what it belongs to. Been surfing the web since 3 AM this morning trying to find info on it, but kept coming up facing a stone wall. I can't tell if it's a dated 69 unit or a 79 unit. Posi unit works fine. Based on the date of the differential H 15 9 and the carrier 410409 N dated H 2 9 and the ring gear part # 1 GM 1252065 17 41 dated 9 79 I can't tell if I'm coming or going. The passenger side tube has what may be a 7 but only has the bottom leg then KA   G267  1. I sure could use some help on this. I plan on just selling the posi unit but if the housing is a good needed housing I would rather see it go to someone that needs it.

Thanks,
Gary
GaryC

'UNRESTORED' 1969 Cortez Silver X33D80 Z28

1968RSZ28

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Re: 12 bolt width/8.5 10 bolt posi questions
« Reply #1 on: March 23, 2008, 11:17:49 PM »
How wide is the Camaro 12 bolt backing plate to backing plate? I measured mine at approximately 53". Is this correct?

Yes, that is approximately the measurement on my car.

Paul

hotrod68

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Re: 12 bolt width/8.5 10 bolt posi questions
« Reply #2 on: March 24, 2008, 03:48:34 AM »
The '69 10-bolts were 8.2" ring gear, so you have a '73-up rear. If I remember right, after '72 the 12-bolt was gone and all the axles were 8.5" after that. It couldn't be for a '70s Camaro--they were all leaf spring cars. My 2 cents and good luck!
HotRod'68  1968 SS350 coupe undergoing frame-off resto/rod. 386/350/4.11s
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