Hi guys I need some help. I have a 3.08 rear end stamped SC on the axle tubes and I want to go to a posi. Its a 67 442 auto but im putting a 455 in and I want to beef up the rear. Im hoping to push 500+ hp through that baby and I want to be able to still drive on the street with occasional trips to the track. What are the best gears I can fit in this thing for what I want? Can I get a 3.90 posi in there? Its an 8.2" BOP 10 bolt. I think I read somewhere the steepest I could go was 3.55. Thanks for the help.

 

I don't have the experience to answer your question. But I know that the 1967 used both the 8.2 and the Type O which is an 8.5. The rear end guru's will need to know which one you have before they can give you the information you need. Can you take photos of the inspection cover? That would help key out which one you have.

John

 

Yes sir. Like I said its an 8.2" with the clamshell cutouts and 10 bolts on the cover. The gear has 40 13 GM 8 66 PO. The housing has the 2 ribs with a stamp reading 9783393 with a little j286 above that. I think its a pontiac.

 

Yes, 10 bolt 8.2 if the upper ribs are converging to the pinion snout Also on the bearing caps it will have < > signs. You can fit ANY gears set from 2.56-5.13 in the Pontiac Buick or Olds 8.2 from 1964-1967

Carrier breaks are as follows
2.56-2.78
2.93-3.23 <<<< Here is where you fall with the 3.08
3.36-5.13

so to install3.55 or 3.90 or 4.56 you will need a 4 series carrier (3.36-5.13) and then your gear choice. Probably a good idea to replace the bearings if this is a original rear with original bearings and seals etc.
I carrier 3.55 3.90 on the shelf and even have 4.56 and 3.55 Good used Richmond gears if that helps.
I have also deals on the posi units (Eaton and Auburn) you need running a end of the year posi sale Jim

PM for prices.

 

Hey Monzaz,what kind of fluid do you recommend in the eaton differentials?

 

These companies want you to use standard conventional Hypoid gear fluid NOT synthetic ... weight does not matter brand does not matter. Filling the rear completely DOES. checking it at least once a year - change fluid after about 500 - 1000 miles if new gears were installed.
Limited slip additive should be used with STEEL clutches always. If you are using composite or carbon fiber you may or maynot need it as these materials work slightly different than steel and will not transfer the noise as steel does if they do catch and slip -

So hope this helps some.

Jim

 

monzaz, sent pm.

 

If you are interested,I have an original 4-pinion posi unit and GM 3:91 gears,for that 8.2".

As far as oil goes,I put conventional 85/140 in everything that I build.

 

Thanks to monzaz! Great advice, and great customer service! Got me an eaton posi series 4 with 3.90 ring and pinion for a great price. Shipped right to my front door within 4 days. Poor guy had to deal with my constant questions and responded immediately to everyone asked. Great job Jim! Thanks again.
Ryan