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#81343 08/12/2007 3:19 AM | Joined: Nov 2004 Posts: 117 Wrench Fetcher | | Wrench Fetcher Joined: Nov 2004 Posts: 117 | I've got a '72 C10 with a stock 12-bolt GM corporate open rear. Gonna be rebuilding the rearend anyway and would like to upgrade to a posi as long as I've got it apart. Are 12-bolt truck rears pretty much all the same? That is, if I found a posi out of an '80 Blazer (for example) with a GM 12-bolt, should it work in my '72?
Thanks,
Brent | | |
#81344 08/12/2007 3:29 AM | Joined: May 2006 Posts: 8,351 'Bolter | | 'Bolter Joined: May 2006 Posts: 8,351 | If it's a 12 bolt truck diff, then yes, it'll work. But you'll need to be looking for no later than about '77. GM went to the 10 bolt after '78 for most 1/2 tons. Also, be wary of pre '63-'65 diffs, they use a different spline (17 instead of 30) with a mid year change in '65. If you truly want a Posi, check out the aftermarket. Lots of choices available, new, plus gears if you want to change the ratio.
Bill Burmeister
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#81345 08/12/2007 3:40 AM | Joined: Nov 2004 Posts: 117 Wrench Fetcher | | Wrench Fetcher Joined: Nov 2004 Posts: 117 | Thanks for the info! For right now I am forced by finances to avoid any really decent aftermarket stuff (Eaton, Auburn, etc.) but GM posi's seem to be available at reasonable prices. It's not necessarily a permanent solution but as long as I'm in there I figure it would be a shame to not at least consider a posi. :-) | | |
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