66 Pontiac Grand Prix 12 bolt posi

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66 Pontiac Grand Prix 12 bolt posi

Post by motocip » Mon Jul 06, 2009 9:11 am

My car came with a 2.73 open rear end, factory code (UB). I acquired a factory posi unit that currently has 2.41 gears, factory code (VB). I have both complete rear axle assemblies. My goal is to have a posi unit with 3.55 gears. What are my options? Can I use any of my existing parts? What is the largest gear that will fit on my current 2.41 posi carrier? My axles have 31 splines and bolt in, no c-clips. My pinion gear has 28 splines. Thanks in advance.

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Re: 66 Pontiac Grand Prix 12 bolt posi

Post by monzaz » Fri Jul 10, 2009 10:49 pm

Ok well we have trouble here at the moment... The full size Pontiacs are NOT supported by aftermarket gears at this time...I say at this time because There is a gentleman in Texas working on the gears as we write.

Some of the full size pontiacs did come with 3.73 and 4.11...BUT they are extremely VERY hard to find and in good shape.

You can with the 2.41 posi use up to about 3.08 with a spacer.

I had a set of 3.23 that came through USPS but they lost the pinion gear...:O NOT GOOD... I have the ring gear brand new and NO pinion :(

The 3.08 3.23 and even the 3.42 might be gettable...I do believe 3.55 is a optional pontiac ration in the big cars in 68 69 years.
J D Race

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