I have a 1967 Delmont 88 with a 455 and a 4 speed manual. The rear is a 9-3/8" O-type posi with 2.73 or 2.78 gears. It is in good shape but it's a bear to pull out with (since the cam is larger than stock).

I can get an 8.5" 3.08 posi for $350 from a 1993 Caprice police car. It's my understanding that this rear will bolt right into a 1967 B body.

I am concerned that this rear rear will hold up to a slightly built 455. Has anyone done this?

Also, has anyone started making gears for the big O-type rear yet?

Thanks,
Chris

 

WRONG.... Will not even be close to fitting... Shocks are in the wrong spot, lower control arms wrong, spring perches wrong, anything else ?

Just remove the BIG cam and recam with a good smaller torque cam
260-268 duration cam

 

Also, as far as I know there aren't any aftermarket gear sets for these differentials.

 

tHESE DIFFERENTIALS WOULD BE REFERENCING THE oLDS fULL SIZE CAR REARS 12 BOLT COVER 12 BOLT RING.
Buick 9.3 is another rear that is totally obsolete to aftermarket parts too.

Pontiac 8.875 is the only FULL size rear from the 1965-1970 era that has a gear set in the aftermarket being 3.55 gear sets.

Pontiac and olds do share the Pontiac rear - The low HP Olds got the Pontiac 8.875 rears so there is that option if you need a solid big car rear.

I have a shelf full of posi units and 3-4 sets of 3.55 NEW gear sets.
Now the problem is that is all expensive stuff. LIKE most of the big car stuff.

Jim
J D

 

That's cool. I didn't know that there were aftermarket parts for Pontiac differentials. The B/C body Oldsmobiles are under appreciated.

 

There are just non left... Jim

they got derby-ed to death

 

 

Thanks!

I have a posi 2.73 or 2.78 but could use gears. Will 3.55's fit in that unit? If I remember correctly from an earlier post, 3.24's are the lowest that will work in the 9-3/8" unit with 2.7X's. Since I don't race the car 3.24's would work although 3.55's would be even better.

Have any of you guys put in an aftermarket rear that has the same spring and shock perches as well as trailing arm connections as the B body that would take a Ford 9"?