GT-37’s with 4:33 gears?
 

Just read an interesting article about the GT-37’s from the early ’70’s. Was surprised that 4:33’s were a factory option. That’s a lot of rear gear for the street and I’m wondering if anybody here has experienced a ride in one of those beasts?

“In 1971, a Pontiac T-37 could be ordered with a 455 H.O. V8 engine, 4-speed M22 Muncie "rock crusher" and 4:33 rear gears.”


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My Uncle sold at least one of the "Pontiac T-37 vehicles a 455 H.O. V8 engine, and 4:33 rear gears."

I am pretty sure that the car was a Turbo 400 car though. Same 4.33 Gears though.

I must have installed that front sway bar at least 5 times on that car.
The owner would remove the sway bar to get the front end to rise quicker.
He would leave it in the Pits at US-131 Dragway in Martin Michigan with his trailer.

Then during the week he would drop off the car at the dealership and I would re-install the sway bar for street driving again. Jim Luitkins either owned the car or had a similar GT-37 at the same time. He was a Pontiac Guy.

Tom V.

http://jimluikens.com/wp-content/upl...scleCarRev.pdf

I really don’t know about that 455 4.33 rear gear deal for a option. as the factory would then be selling a car who’s motor would be guaranteed to blow up in no time flat!!!

If such a thing was done at all then the gears would have been swapped in after the car was sold to the customer by the dealership and then install by the selling dealership.

That 4.33 rear gear deal however was a option in the 389 and 400 ram air models up to 1970, in fact in A body and F body cars ordered with the RAII through RA4 motors 3.90 gears where mandatory with the 4.33 gears being optional.
Also the RA4 motors could not be had with AC due to the fact of how high these motors where always spinning!

I mean gez! Full on race cars with 455 motors running under the 10 second range rarely run over 4.11 gears , so I can’t imagine a need for such in a pure street motor that is fully out of steam at 5500 rpm!

4.33 gearing was not avail as an option in the HD 8.2 STT rear in '71 model A-body's. Factory installed,
3.90 was as low as it got for '71 models. That was special order behind non AC 400 4bbl A-bodys. It's also an extremely rare chosen option for '71. I have one copy of a factory invoice of a 400 M22 3.90 special order early 71 GT-37. GTO wise, less than a handful of '71 400 GTO's have surfaced w factory 3.90 gearing.

'71 model T-37's & GT-37 factory equipped with the 455 HO engine received 12 bolt rears built out of the McKinnon plant. Ordered with the 455HO engine, & without factory AC, the gear ratio was 3.55. With the M22 or M13 HD 3spd and factory AC, 3.31 gear was required. No 3.73's, 3.90's or 4.33's from the factory.

There is a factory 4.33 gear that was listed for Chevy 12 bolts, but it was an over the counter item.

I ordered 3:90 gears but the dealer received a notice that they were not available.
400 4bbl could have 3:90’s but that was the lowest in any one available in ‘71.
Remember that 71 was the first year of low compression and the biggest cam was the 068 so lower gears were not wise as the red line was not very high, even for the 455HO.. Nothing on the MSP. I even wrote a note on it about no reference to special gears.
Still have the MSP.
Can you imagine the rpm w/4:33’s.

Also, 4.33:1 was STANDARD gear ratio on 1966-68 RamAir GTO.

Please prove to us that in 66 to 68 RA 400 motors that as in your post 4.33 gears where standard off the assembly line.

Don't fear the gear :D

I believe you are correct Kenth

455, manual trans, 4.33 gears, and stock Pontiac rods. What could possibly go wrong?

Yes, my point exactly!
At 80 mph with 4.33 gears and a 28” tall tire you would already be over 4000 rpm and at 110 mph the revs would be over 5700 and well into busting rod time!

Had 4.33's in my 67 ram air GTO. Drove all the way from Ohio to Florida. Never again will I go with that low of gear ratio1

From Pontiac:


http://forums.maxperformanceinc.com/...1&d=1612198247


:)

This is for a Firebird, but the Tempest section is at the top.
Also was for the RA II but RA I was the same.

:)

As we all know, memory can fail and sometimes the imagination can take over. Not that it is wrong to have fantasies, but sometimes you have to check the facts from the source and in this, and many other cases, you can check the factory literature.
Wouldn't it be easier to check the factory information instead of chopping something out of thin air?

FWIW

Looks like Wallace's Pontiac Document and items # 347, #358, & #462 options kind of shed more light on the subject vs "Why would they do that?", "They never did that!" and some people do not understand that the HOT SET-UP for racing was the GT-37 "Race Cars" Pontiac was selling to the public, (actually a few special people who raced and knew what to order).

Tom V.

That special GT-37 rear axle (12 bolt) was also offered with some special Service Package axle shafts for that 12 bolt rear.
My buddy from New York ran that 12 bolt rear, special axles, etc installed under his 64 GTO race car but with 4:56 gears.

An even lower gear ratio vs the 4:33 gear 12 bolt package.

Thats a slightly strange way to list things, as it leads one to believe that with any RA option with any trans you where locked into a given gear ratio, or even on a base line motor once you checked the box to get a close ratio 4 speed you where then locked into a given ratio once again!

That is true for the most part when you ordered vehicles of a given configuration in the early 70s. You got to choose the engine, the trans, the exhaust in some cases, A/C and Non-A/C, and the tires (white wall, black wall, etc, but the size was fixed as was the basic configuration with the "Special Package".

A Lot of a given package were assumed to be part of that package and you paid for the package, (sometimes a bunch more money too).

Tom V.

What's info on that car?

I had a 65 GTO tri-power close ratio Muncie with a 4.33:1 rear. I remember it being a 4 pinion unit when I had the cover off. It was my wife's daily driver for about a year. It was pretty miserable for her to drive, but she got the hang of it. The manual steering was more of a chore for her than the gearing. Federal speed limit was 55 when we owned it. So it was tolerable at 60 MPH. It was pretty punchy around town, but not a good choice for a Pontiac V-8. My friends 69 Ram Air III GTO was quicker in a street race. It had a 3.55 or 3.23 whatever was standard with a 4-speed. I was told the 65 came with the 4.33 ratio. Bought it from the original owner but no PHS back in those days.