Question:

I have a 1970 Cutlass Supreme with the "o" type 12 bolt differential & and a 2.60 gear. I want to increase that to a 3.42 gear with Posi. Is that possible with off the shelf parts? Anyone with some practical experience who would be willing to post some options, I would appreciate it.
Later upgrade will probably include a trans with overdrive.

Thank you

 

It's more likely that you have either the 2.56 or 2.78:1 rear as Olds did not use a 2.60 in 70. There is much debate about the "O" type rear ends. I am no expert in this arena, so I'll refer you here:

Try the Olds FAQ for more info: http://oldsjunction.classicoldsmobil...ential%20Codes

And contact Supercars Unlimited.

www.SuperCarsUnlimited.com

Supercars Unlimited
8029 A SW 17th
Portland, OR 97219
PH: (503) 244-8249
FX: (503) 244-9639

 

Thank you! I have found that confusion as well. It looks like I will need to count splines on my axel to confirm exactly what I can fit in the carrier or if I need a new carrier.