Posi Rear End For GS, Optional?

I was getting some gas today and I ran into one of the few guys around Oregon who has a A-Body. We talked for a few and he said he bought his car awhile ago and that it was a numbers matching GS 350. We started to talk about his rear end and he said that it was not a posi one. So my question is was there any 70-72 Skylark GS's that did not come from the factory with a posi rear end? It is possible the previous owner of the car pulled it out, since he did the same with the original interior, this new owner of the car I spoke with said the thought the guy he bought it from had taken out the interior to put into a conversion GS, WHY? would anyone part out a #'s matching car when it is more than restorable and put the parts on a clone? This does just not make any sense to me, maybe it does to you.

 

Yes all GS's didnt come with posi rear ends.

 

My 71 GS455 came with a 3.08 open rear originally.
My 72 GS350 came with a 3.08 posi rear originally. When that blew back in the late 80's, I got the rear out of a 71 (or 2) GS455. It was on open 3.08 rear.

 

I thought some GS's did indeed come with posi units? Why does the 3.42 posi unit come to mind? Did any GS's come with this unit? I know a few guys who have GS's with posi 3.42 and I thought they might've come that way? I think the Stage 1 used the 3.42 but that's off topic.

 

They were optional.

 

Posi s

I THINK I REMEMBER o No:


that in the early GS years the posi was part ofthe GS pkg. [65-66] [high performance eng, heavy duty springs, heavy duty shocks, quick ratio steering,low restriction exaust,GS markings] Then later the GS pkg was changed to a Type of car and then the posi became optional for that car.
I do remember buying a 68 Riv GS and having to pay for a 3:42 posi diff for the car. :Brow:

 

My 70 Stage 1 came with a 3.42 posi, it was an A/C car...

 

Just look in the assembly manuals

I recall in 71, you could get a 445 with open 308 STANDARD, and for the 350 engine, the 308 open was STANDARD.

In 71, the Posi was ONLY standard on the stage 1 cars. The posi may have been standard on all manual shift cars (I can't recall for sure). o No:

 

Only the Stage1 option in all years contained the posi rear standard.

Without the Stage1 option, the posi rear needed to be ordered separate.

NYSTAGE1 - is your car a factory stage1? If so, please consider registering it - thanks!

 

If it was a non AC stage 1 in 1970 I believe the standard posi for US built was a 3.64, 8.2 . I know this was true for a 4 speed and I think it was true for an auto but I have never owned a non AC auot stage 1.

 

Yes Jim - in 1970 non A/C Stage1 cars received an 8.2 inch 3.64:1 rear while A/C cars received 3.42:1.

In 1971-up, all Stage1 cars, regardless of A/C option, received an 8.5 inch 3.42:1.

FWIW - In 1969, I think the Stage1 cars received a 3.64:1 rear (also 8.2)

 

Marco, factory Stage 1.... Not original motor. I know people have been telling me for over ten years to join the GSCA and other Buick clubs. I used to race it in the NMCA Stock ET class it was in some NMCA mags in the mid 90's and and muscle car magazine in March 1995 issue....

 

Also I recall a 70 GS 350 (US built )may have been standard with a 3.23, 8.2 posi. We have run that gear is it is the best combo for open highway and street with a TH 400.

 

I thought stage 1's came with the posi rear standard :bglasses:

 

My 70 non-A/C Stage 1 GSX came with a 3:42 rear (verified by Wayne Roberts). Was this a special order?

Brian

 

Hi Brian -

Do you have the build sheet? That's the only way to prove your GSX came with a 3.42:1 axle.

Did you get the axle codes off the rear and know the rear is original to your GSX?

It sounds like a special order, or a mistake.

What did Wayne give you that tells you it's a 3.42:1?

 

Marco,

The rear end is not original. When I got the car it had a 3:90 12 bolt posi in it. I put in an OO posi from a 70 Stage 1. Wayne sent me the typical build sheet information based on the VIN and it includes "G-1 Performance Axle with Positive Traction 3.42 Ratio".

Is it possible this is just a generic option description? I can e-mail you the information Wayne sent me.

Brian

 

Hi Brian -

It does sound like Wayne's generic GSX option description - I wouldn't worry about it.

Everything I've read/heard to date stated that in 1970, Stage1 cars received 3.42:1 and non-A/C cars received 3.64:1 axles.

You should have an 'ON' axle :3gears:

:beer

 

Marco,

Thanks for the information. I was looking for a 3:64 rear but stopped when I got Wayne's information. I guess it's time to start looking again.

Did I ever send you the information for your registry. I forget o No: .

Brian

 

Yes you did Brian - thanks for the support :TU:

...and Happy New Year :beer