Hello, the new guy here.

I have a 67 Cutlass convertible that currently has an O type 10 bolt 8.2" rear end. This spring one of the outer axle bearings seized and ruined the axle shaft so now I am looking into my options for upgrades to a limited slip and 3.90 gears while I have it apart. After doing some research I am considering going to a BOP 8.5 10 bolt as it appears to be a direct bolt in with exception to the drive shaft length and would give me a little more strength.

Future plans for the car include a 2004R trans and potentially a mild 455 sometime down the road. Looking for a performance street car that will rarely if ever see the track. Just don’t want to get beat by any more girls in VW Gulfs from a standing start…

Staying with street tires I should be safe with the 8.5 correct? Any recommendations on sources for parts or complete rear ends? I have no issue building it myself just looking at my options to get the car back on the road.

 

Well depends on what you have left in the olds rear as it may save you money and will be just as good on the street as a 8.5 10 bolt gm rear.

Have you opened the 12 bolt olds rear yet?

Axle shaft spline count? 28 or 31?

There are parts for both 12 bolt olds and 8.5 10 bolt rears

3.42 3.90 12 bolt olds gears '
3.08 -5.57 ratios for 8.5 10 bolt.


So you have to find the 10 bolt 8.5 housing and buy all the parts

Olds 12 bolt you have the housing and ??? able parts inside.

You can PM me and I can quote out prices for both complete if you like just parts or whole rear with or with out brakes ...drum or disc... Just comes down to money.

As stated both rears have parts in the ratio you want so it is a flip of the coin.

Jim
J D

 

Thanks Jim. I will be in touch.

The axle I have is a 10 bolt 8.2 , not what it typically referred to as a Type O, I guess?? I am really just looking for the most economical option for building a depending rear end to serve my needs and I question if building up the axle I have is worth it.

I also see you were selling replacement axle shafts for the 10 bolt 8.2 so either way I’ll be in need of parts.

 

Stick with Jim, he hooked me up with all my parts for my 12 bolt "O" type rear. He is very willing to help and his prices are great also, I have looked around. and he saved me a good amount of money and pointed me in the right directions.
Bill Caprio