[elefantrider]

Anyone know what gear ratio is an "AO" axle code on the build sheet? Car is a '64 tempest originaly equipt with a 326 2bbl 4 speed, no A/C. Unfortunatly, i can't jack up the car right now to check.

[Pecosbill]

You really don't have to even jack the car up. Just get a wire brush with a handle on it, lay down on your garage floor and start brushing. On the 64 the axle ratio is stamped into the housing just to the right of where the center section of the rear end attaches to the axle housing tubes. It is on the passenger side and faces the rear of the car. It's really not hard at all to clean it up and read it.

[elefantrider]

pecosbill- "AO" is the code, which matches what is written build sheet. I just don't know what that means. All the charts i've seen on the internet have been for '65 and later. Do you know where i can find a chart for '64?

[Pecosbill]

According to the documentation I received from PHS on one of my 64's one letter axle codes are as follows:

A = 2.56
C = 2.93
D = 3.08
E = 3.36
F = 3.55
K = 3.23
P = 3.90

On the front of the PHS documentation under "Axle Ratio" on my car it says "K0" which is correct for my car which does indeed have a 3.23 rear end. I don't know what the "0" stands for. If you've got "A0" on your build sheet I would suspect that it is a 2.56. Hope this helps.

[elefantrider]

thanks pecosbill. That's the listing i was looking for. A 2.56 ratio is not very inspiring, even if used with torque monster engine like a 455. It looks like i'll have to budget for a change in the near future. It's difficult to imagine this high gear came with a 326 2bbl powerglide combination but i guess the car must have been considered a grocery getter in its former life. The cool little 326 flag emblems on the fenders seem to suggest more than that.

[b-man]

A 2.56 ratio is not very inspiring, even if used with torque monster engine like a 455.

It's a nice ratio for the freeway. You can still downshift into 2nd at 80 MPH, and have it pull past 100 before you shift to 3rd (TH400). My '64 Tempest easily ran high-13s with that gear (using 1st and 2nd only), with a near-stock 455.

It's difficult to imagine this high gear came with a 326 2bbl powerglide combination

Imagine that same gear with the standard 215-inch six and a 2-speed. Yep, mine had that before I went to a V8. It would pull all the way to 70 MPH in low, a very smooth and pleasant car to drive. Just not very quick.

I miss the 20 MPG it got as a stocker, but I hated being so easily passed and cut-off on the local freeways.

[elefantrider]

That goes to prove that Pontiacs don't need a lot of gear. When i changed from 3.23s to 3.73s with my 389, i didn't pick up much- maybe a couple tenths if that.

Now i'm wanting to put the 3.23s back in.

Can i make my NOS 4 pinion posi work with 3.23 gears by turning it down or using a spacer?

I have an old 2 pinion posi that was working when i took it out but i'm not sure it will last much longer. I hear the 4 pinion units are far more durable. The car will see some roadrace track duty.

[b-man]

I wouldn't think you could mod the 4-series to run a taller gear than the 3.36 that fits it, nor would you want to.

A 4-pinion NOS 8.2 posi is worth plenty to a GTO restoration buff. Sell it and you'll get most of the dough to build up a much stronger 8.5 rear from a '71-72 Buick that's a bolt-in but 1" wider.

The sealed axle bearings are one of the weak points on early 8.2s, especially for a road race car.

Check out this thread and see what ol' Pinion head says about the different rear ends, one with tapered bearings is what you want.

Click here.

I'd gladly 'dispose' of that nearly useless 2.56 rear and possibly even that 2-series posi for you. All at no charge to you for this service of course, just trying to be a good neighbor.

[elefantrider]

Very enlightening to say the least, B-man. Thanks for pointing that out.

So the 8.5 buick from '71-'72 uses the tappered bearing with bolt in axles? It doesn't seem like many gears or posis are available for this axle. I couldn't find it on richmondgear's site.

It seems the c-clip rearends (10 and 12 bolt) have tapered bearings, but that would eliminate one weekness while adding another (c-clips). C-clip eliminator kits would probably help.

OPH says that not all 9" have tapered bearings, but i suppose most aftermarket ones do. I see why it is the hot set up for road racing when allowed.

[b-man]

I'm not an expert on rear ends, ol' Pinion head is the one who can straighten you out on any questions you might have. I have read that the Buick 8.5 rear is a good strong bolt-in for the A-bodies.

One thing to keep in mind, the C-clips really don't hinder your choices like you'd think. No need for a C-clip eliminator when you're running rear disc brakes. The caliper will keep the axle from exiting the housing in case of a C-clip or axle failure.

[elefantrider]

I think i saw a posting that said the 71-72 Buick/Olds rearends use tapered bearings. I just sent an email to OlPinionHead to be sure.

I'd like to run disk rear brakes but the vintage racing rules don't allow them. Already, i'm having to make a case just to run front disks instead of drums because our cars weren't equipt that way from the factory. Hard to imagine them wanting a roadrace car with 450hp to run stock drums, but true. Imagine the safety hazard that would be. I'm hoping to make the case based on safety, which hopefully will work. Ahh well, those are the rules... for good and bad.

Heck, if i could have it my way, i'd probably run that kinsler injected ZL-1 motor with 700 HP (pictured left)!