[patox]

Hi, I been thinking on switching my rear end gear for something more highway-able, and this has proven hard.

I have the original 10 bolt 8.2" and 3.90 posi on my 66 GTO vert that is mostly used for cruising on sunny days.

I was looking for a 3.08 for it, and asked summit for advice given the fact BOP's were different than regular chevy's, summit knowable stuff gave me a list of options.. none of them showing BOP compatibility.

Can any one help me on getting the right part n for a 3.08 that will work on my car? or given the fact I originally have a 3.90 my carrier will only accept a 3.36? if so where can I get one?

Thanks in advance!

[propuckstopper]

Two years ago for my 1965 GTO, I rebuilt the original 3.55:1 rear end using an Eaton posi.

Fast track to today, I am currently going through the entire original rear end on my 1968 GTO. Due to the fact that it is an air conditioning car, it came from the factory with a 3.23:1 rear ratio.

I tried to buy an Eaton posi, but they did not come sized for my 3.23 ratio. I contacted JD Race and Restoration and they set me up with an Auburn unit to work with my 3.23 gear.

If I recall correctly, the carrier break for my '68 was 2.93 to 3.23, which Auburn makes but Eaton doesn't.

So, it is an Eaton in the '65 and an Auburn soon-to-be in the '68. Some guys say they really prefer the Eaton posi, but I had no choice for my '68.

With the amount of miles these cars get driven, I think I will be fine with both units.

[patox]

Yes this rear ends are getting hard to find.

Have anyone found an aftermarket 3.08 kit somewhere? The lowest I have seeing is 3.55 what is not a huge different front my 3.90.

Also I have a 68 firebird 350cid automatic that I believe should have a 2.xx or 3.08 at most. Will that one work on the for the gto rear?

Thanks!

[propuckstopper]

Originally Posted by patox

Yes this rear ends are getting hard to find.

Have anyone found an aftermarket 3.08 kit somewhere? The lowest I have seeing is 3.55 what is not a huge different front my 3.90.

Also I have a 68 firebird 350cid automatic that I believe should have a 2.xx or 3.08 at most. Will that one work on the for the gto rear?

Thanks!

When I rebuilt my '65 GTO rear, I bought a brand new 3.55:1 ring and pinion from Richmond Gear (I think it was Richmond).

However, the 3.23:1 ring and pinion for my '68 is not available anywhere in the aftermarket. In fact, I think the closest aftermarket gear available was 3.36:1. Fortunately, my original gears are good enough to use in my current rebuild, so I will go with the original 3.23 set.

It just might be that a new aftermarket 3.08 is not available. You might have to source a good used one, then use the Auburn posi to complete your build.

Happy New Year.

['ol Pinion head]

new Pontiac 8.2 10 bolt 3.36's are avail in two different product lines. They fit the LOW ratio (3.36-5.57) '64-69 Pontiac 8.2 10 bolt carrier. No aftermarket 3.08's or 3.23's for Pontiac 8.2 10 bolt.

2.93, 3.08, 3.23 Pontiac 8.2 10 bolt gears fit the MID ratio Pontiac 8.2 carrier.
Have pulled and sold over 3 dozen sets of nice used 3.23's over the years, and have set up quite a few more sets in rearends. Currently have an early 3.23 set out of a '69, an a '70-72 3.23 set out of a low mile '71.

[rexs73gto]

I don't know if the guy still advertises in Hemmings or not but there was a guy that use to sell all kinds & sizes of rear gears for the early rear ends. The price was good & he did guarantee them.It may be worth your time to look into Hemmings for him if you come up empty here.

[Wilke1]

You can try Franks Pontiac parts, last time I was on there , He had a set of 308s and can pick up a carrier from Quick Performance Inc out of Ames Ia.

[67gtospud]

I rebuilt my 10 bolt last spring. Put in an eaton posi and 3.23 gears. I was hoping for 3.08 but couldn't gear that tall with the eaton. Check ringpinion.com I believe that's where I got my gearset. Was Yukon brand gears.

[jd66]

Have you given a thought to an over-drive transmission? I went with the 5 speed, I see now you can buy a Muncie 4 speed with a over drive type gear for 4th. jd grim 66 gto

[patox]

Yes have though about it more than once, but the car is so original that putting a five speed might be a crime, or to expensive to be done as it should.

What about that overdrive for the Muncie? Any one using it? Thanks for the advice!

[chemnick]

Ol Pimion head:

Trying to send a PM but the system says your PM is full.........................

Chemnick

[GT182]

I bought an Auburn Limited Slip setup from a PY member, with a Motive Gear 3:36 gear set #G882336 from Summit.

Also bought a Pontiac Richmond 3:36 install kit, #RMG 8310401, from Summit.

I haven't gotten it installed yet as the guy that will install it has been super busy. Hopefully it will be installed soon.

[geeteeohguy]

Getting and installing 3.36 gears into your current carrier will solve your problem. If you run 28" rear tires, it will drop to about a 3.23 ratio. Perfect for cruising and performance. I had the 3.55 rear re-geared to 3.36 in my 4 speed '65 25 years ago. You wouldn't think there would be much difference, but it made a huge difference on the open road. Car now cruises 70+ easily, before it was sweet-spotted at about 60mph.