I am working on a 67 CS that currently has a 3.08 open rear in a "P" carrier. I have a 70 Ninety Eight that I will be parting out; however, it has a posi rear. I would like to take the posi out of the Ninety Eight and put it into the 67CS. My questions are:
- Can I take the posi out of the Ninety Eight and install it in the 67CS "P" carrier?
- Is the rear in the 70 Ninety Eight an 8.5?
- If the Ninety Eight is an 8.5 rear would it be smarter to install the hole rear in the 67CS and just change the gears?


Any insight is greatly appreciated. I apologize for the misuse of any terminology or lack of knowing what I have, I am green at this.


Thanks
Drew

 

Unfortunately, those two rears are extremely different and will not interchange.

1- The posi from the 98 rear will not fit into the P housing. Your P type rear is an 8.2" 10 bolt rear and the 98 has a 9.375" 12-bolt type O rear. (according to this thread: https://classicoldsmobile.com/forums...-big-olds.html)
2 - No, the rear in the 98 is 9.375".
3 - The rears will not interchange between the two cars, and the gears will not interchange between the two rears.

If you want to put in a posi carrier, you need to use one from an 8.2" rear.

 

Thanks for clearing this up for me Kenneth. Thought I was on to something. Oh well.
Thanks again