Hey all,
I have a 1969 olds 98 and i belive it has the Type "o" rear end. I was wondering if any of the ring/pinion sets or posi's that super cars unlimited sell will fit my rear end or are those parts for A-body's only?

 

Sorry, it's not. Only the A-body cars used the Type O.

 

I'm Confused, the rear diff cover looks like the typical 12 bolt type 'O'. I've heard different people say it would have the 31 spline type O carrier if it has the 455 which it does. I've also heard that some of these full size olds rears had a 12 bolt ring gear instead of the usual 10 bolt that the type O is known for. Have you ever had any of these rears apart Joe to compare ? TIA!!

 

The a-body has 12 bolt cover SMALLER DIAMETER
Full size has 12 bolt cover LARGER DIAMETER

They both look the same BUT if you put the covers side by side you can see the FULL SIZE CAR REAR COVER is way bigger.

12 bolt full size has 12 bolts on the ring gear
12 bolt a-body has 10 bolts on the ring gear.

There are NO aftermarket parts for the 12 bolt full size rear olds 'O' type. sorry

We have a 2.73 set and a couple of posi units also.

We are trying to retro fit gears into this housing and may have a close candidate BUT we need to machine it to see if it will mesh and or work. TAKES TIME. Working hard on this.

Jim
J D

 

I see, these are a whole different monster as i'm finding out ! I currently have a 2.56 gear in there with the one legger (i did the rotate the one tire with one off the ground trick and got 2 and half turns on pinion to determine it). A posi would be nice even if i'm stuck with the high ratio. It would be cool if a power trax of some sorts could work in there so I wouldn't have to mess with re-shimming it. The car only has 75k miles and was babied it's whole life (little old lady owned it, then sold to a guy that just showed it) so I assume that rear is in excellent shape as is the rest of the car. I got the S manifold and have a spare W so i can put the true duals, and got a set of big valve toro C heads i'm redoing as well so don't have to keep using the lead additive. I switched to HEI as well (I hate points) I know some of you guys might be cringing because I'm taking away from the originality a little but i'm trying to do mods that don't look too obtrusive and look stock appearing.

 

From what I have had & seen,the 68-70 Deltas that came equipped with a 350,had a 12-bolt o-axle center/pumpkin,like the A-body. The 455 cars had the large 12-bolt cover/12-bolt ring gear.