RTTOY

My build will consist of a 455 and a TH400 trans, ID'ed my rear axle today as the original 68' Oldsmobile "O" axle 10 bolt open diff (I counted the carrier bolts). What options do I have for my application?

Assuming i'll be grenading the 10 bolt if I throw in a posi unit, can I simply swap in 12 bolt components (shafts, carrier, ect..)? Or am I stuck trying to track down a 12 bolt olds O axle. I would prefer not to use a chevy housing due to I want to run a W-27 cover, plus my olds throws up hate for chevys. What do you think guys?

joe_padavano

There is no such thing as a 12 bolt Type O. All had ten bolt, 8.5" ring gears, despite the 12 bolts on the cover (and despite the fact that many sellers advertise them as "12 bolt" axles. Unless you plan to regularly drag race this car with slicks, the 8.5" axle will probably be fine, particularly with the bolt-in axles. Even if you do find a Chevy 12 bolt housing for an A-body that isn't priced like it's solid gold, you still have the C-clip axles to deal with. You can, however, get a W-27 cover that fits the Chevy 12 bolt housing. Supercars Unlimited should be one source. If you're really worried about strength, get a Moser 9" housing. They make them as bolt-ins for the A-body cars.

monzaz

OK well if chevy 12 bolt is not an option as your olds screams

quote' I would prefer not to use a chevy housing due to I want to run a W-27 cover, plus my olds throws up hate for chevys'

Can you imagine what the car would do with a F O R D part under it. The OLDS would probably run you into the first tree or cliff it comes too....lol.

If you have some money I can help you keep you ORIGINAL olds rear under the car and get you the strength you need.

I have an ORIGINAL SUPER DUTY olds posi 31 spline unit still on the shelf here!!! We can order you up some Moser custom 31 spline axles JUST like it had in the day...BUT WAY STRONGER!! I have a set of ORIGINAL 3.91 gears also. It will not be cheap BUT it will be one BAD A-- OLDS original rear.

I do Have a few housings here I can build the whole thin gready to bolt in if you prefer that way too. Just PM me and we can discuss your needs. I have other options too if you want to use a different GM housing...we have Olds 71 72 10 bolt 8.5 rears that will have the strength of a 12 bolt and bolt in axles with many gear choices that will also hold your big block power.

Good luck in your choice. Jim

J D Race.com