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BOP Rear End question

5K views 5 replies 4 participants last post by  lust4speed 
#1 ·
Whats up guys do you know where i could find a posi-unit for my 8.2 10 bolt BOP style 27 spline axle rear end? i know these rear ends arent popular and thats an understatement, but there is nothing wrong with the rear end just dog legged and has a tired highway gear in it, it is in my 1968 Buick Gran Sport (originally a 350 car but have 70 stage 1 455 in it), i plan on using a 3.55 gear, thanks guys and if i didnt give enough info let me know, and one other thing im not worried about price.
 
#2 ·
It seems that the B,O,P, rears are usually equipped with highway gears I am pretty certain that to go to a 3.55 you will need to change the case. The one you have is limited to 3.08 and lower numerically gear sets. I also am looking for a posi for a early 10 bolt chevey and found that Auburn gear does make the cone type clutch positraction and richmond makes to gearsets for it. I found these in a Jegs catalog. Good luck sounds like a great ride!
 
#4 ·
79 Malibu327 said:
i have this info page http://www.atlantabuick.com/Specs.htm in the rear axle ratio section it shows different gear sets that the GS cars came with, some as numerically high as 3.91:1 and they all used the same case so why couldnt i go to a 3.55 gear in mine as long as i had the proper carrier
;)
Sorry what we have hre is a play on words, what you call a carrier is what I call a case so we are both right! what the posi case (carrier) bolts into to a housing (case) just a play on words depends if your a southern boy lol ps also call a case, carrier a pumpkin .anyways yes the matching carrier or case will determine which gear ratio you can use. some manufacturers make a spacer or even a thicker gear to compensate for case differences but I am pretty sure they dont for bop models.
 
#5 ·
79 Malibu327 said:
Whats up guys do you know where i could find a posi-unit for my 8.2 10 bolt BOP style 27 spline axle rear end? i know these rear ends arent popular and thats an understatement, but there is nothing wrong with the rear end just dog legged and has a tired highway gear in it, it is in my 1968 Buick Gran Sport (originally a 350 car but have 70 stage 1 455 in it), i plan on using a 3.55 gear, thanks guys and if i didnt give enough info let me know, and one other thing im not worried about price.
GM BOP 8.2 inch axle:
Number of cover bolts: 10
Number of axle splines: 28
Diameter of ring gear: 8.2"
Number of ring gear bolts: 10
Pinion Shaft Diameter:
Pinion Splines : 27

The Precision-Gear GM Track-Lock, and Auburn Pro-Series limited slip/posi units are available but NOT cheap.

This information and more on the 8.2 can be found here.
 
#6 ·
Two of my friends have installed the Eaton posi carrier with the 3.55 gearset and they are happy with it. Both friends purchased the gears and posi as a complete set on ebay.

The 3.55 ratio is available new, but for some reason, the gear manufacturers for the 12 bolt and both the BOP and Chevy10.2 gears do not make any higher ratios. So if you were looking for a 3.08 or 3.23 you would have to search out a used set.
 
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