65GS.com - Buick Gran Sport Enthusiasts!
Drivetrain => Differentials, Axles & Brakes => Topic started by: 1bigdog on February 02, 2012, 03:58:09 PM
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Hi All, new to this forum. I just purchased a 65 Sky Convert. and am planning some running gear updates for it. I was surfing the local craigs list and found a couple of posi rear ends, one out of a 75 el camino with 3.25 ratio and another from a GN with a 3.73 ratio, both are 8.5" units. I plan on getting a 200-4r tranny. So a couple of questions:
1) which gear ratio would you all recommend for this car
2) which of these to rearends would be the easiest to install in the 65?
I don't plan on hitting the strip just want something that is nice to do some crusin around with decent performance and milage. Currently the car has a 300 in it for a motor, but that could change down the road as well.
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Neither rear will bolt right in since the control arm mounting points are different. There may be adapter control arms avail to put in the GN rear, but that adds a lot to the cost. But maybe those are adapter control arms to put an old rear in a GN? :icon_scratch:
An 8.5 inch rear from a 71-72 Skylark or cutlass are the ones to look for. Gears are easy to find for those.
Or just get gears and a posi for your 8.2 rear.
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Your car most likely has a set of 2.78 gears in it. As Walt said, the 72 and older rears out of any GM A-body car will fit. Keep in mind though that andy 68 and newer rear end is about 1" wider and will give you a wider rear track width. I am with Walt--change the gears in you existing rear. With an overdrive transmission, you can get a set of the aftermarket 3.90 gears and Auburn posi to go with it.
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Great insight, thank you.
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Jim 'Monzaz' has extensive experience with the Buick rears. Check out his site here:
http://jdrace.com/ (http://jdrace.com/)
He's likely to have some used parts or can set you up with new stuff at a great price. :thumbsup: