65GS.com - Buick Gran Sport Enthusiasts!
Drivetrain => Differentials, Axles & Brakes => Topic started by: Weldar on December 16, 2012, 09:17:15 PM
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Some interesting information.
Dwaine
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Thanks for posting the article. I read this magazine too and saw it. I was pleased to see the BOP axles get some print space. I do feel compelled to point out one detail in that article that may mislead some people. On the 3rd column of the 1st page, it lists the Buicks as having the BOP axle form 64-71. In reality, Buick purchased all the A-body rears from Pontiac from 64-67. Most of the 64-66 Buick cars I have worked on even had "Pont" stamped on the upper rear control arms. In 68, Buick designed their own rear that is very similar to the Pontiac rear, but very little interchanges--this is the rear that has different size bearings on each side of the carrier, has a larger big pinion bearing, and uses 7/16" bolts to hold the ring gear to the carrier (pontiac rear used 3/8" bolts).
I hope this helps keep down confusion amongst the Buick folks.
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The early Pontiac rears do have differences from the Buick and Olds versions. As Mentioned in the article, Pontiac rears have an extra rib on the center section.
I'm not convinced the width increased in 1966 as the article stated. My 65 GS rear is the same width as my 66 and a 67 rear. I've read Pontiac rears might be an inch wider.... Remember the Pontiac 'Wide Track' ad campaign?
I do have a narrower '64 Olds F-85 rear. It was a 3.08 posi and also had the smaller upper control arm bushings. '65-up bushings were a larger diameter.
Jim Monzaz has a very informative site here:
http://www.jdrace.com/diff_id/10bBOP_Early.htm (http://www.jdrace.com/diff_id/10bBOP_Early.htm)
He's also a good source for parts and service. He's a Buick guy too :thumbsup: