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Discussion Starter #1
Hi i have a 67 lemans with the original engine and trans. I'm wondering how the 2 speed powerglide will perform once i finally get the car up and running. I've heard that some people really like the powerglide for racing but im hesitant to believe that. How is it on the freeway as well? I'm not too worried about gas mileage because i know its not going to be good anyways but will it be at a super-high rpm while going 70-80? This is my first project and im excited to get it started. Im thinking of getting a 4 speed manuel tranny instead. Any advice?
 

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Don't know how they are at freeway speeds but a lot of people raced them 'back in the day'. Look up 'Art Carr', 'Art Carr Performance Products', or 'Art Carr Transmissions'.
 

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Discussion Starter #3
thank you but i was looking for more of a personal view from someone that has owned a powerglide but thanks for replying.
 

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2 speed trans

Well as far as freeway speed vs. RPM, If you are thinking about installing a modern over drive trans, then there would be a 1000 or so drop in freeway driving RPM, a tree speed TH 350 or 400 will have the same final drive as the two speed so it would be the same there.
But the three gears will give you a performance for street driving,
Our 65 has the ST300 2 speed, the buick based trans, I would think that is what you have.
It works fine and a 60-70 freeway speed is around 2200/3000 RPM range, we are running 3.08-1 rear end.
hope this helps
 

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Sixt5 is correct. Not a PowerGlide. Suoer Turbine 300. No amount of modifications can make ST-300 "act" like a 'glide.

Drag racers use PowerGlide in LIGHT cars (under 3,000 lbs.) for best results in bracket racing. Often, 'glide cars are 1/8 mile "specialists". Only one shift... Heavier cars generally use TH400.

TH350 will literally bolt right in. Adding the lower 1st gear changes the entire "character" of the car. It will act similarly on the highway, but low-end performance is DRAMATICALLY improved, expecially when you have "tall" gears (3.23-higher ratio, lower "numerical").

If "originality" is not the primary concern, TH350 for a mild engine and TH400 (needs a bit of "adaption", but well worth it) for a "hot" motor...

FWIW

Jim
 

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I've owned and driven GTO's with the Super Turbine 300 2 speed...it's a strong, dependable unit, but it makes the car a non-contender with it's 1.87 first gear ratio. A switch to a TH350 will literally transform the car. I had a clean 64,000 mile '65 hardtop back in the early '80's, and it's biggest performance "drawback" was the 2 speed tranny. I had a near identical car at the time with a 4 speed, and it was a night and day difference.
 

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2 speed trans

If you do not mind the 2speed trans, the super turbine 300 is a more responsive transmission then the chevy power glide, Buick two speeds where known for good power tranfer a hydraulic and mechanical mix around a 70/30,
But as stated a TH350/TH400 is a better performer.
 

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Discussion Starter #8
thank you for all of your responses. im looking at the 700r4 has anyone installed one of these on a 326 before? There is no driveshaft in the car right now so that's not a problem. if not that im looking to put a manual transmission as well. originality is not a concern.
 

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A guy on the "other" forum (py forumsonline) runs the 700R4 in a bunch of his Pontiacs, and drives them literally 100's of thousands of miles. He tows trailers a lot, too. It's a simple conversion, and will net you great power "off the line" and excellent fuel economy going down the road. It's a common and prudent conversion.
 

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If wanting to go "OD", TH200-4R (NOT to be confused with TH200, a completely different "animal", and major POS) is superior to 700. The trans guys I know say to use that one, with an upgraded sun gear and shell, and it will out-perform and out-live 700 behind an engine with low-end torque. 700 was designed for small block and V6 Chevys. 200-4R will literally bolt right up to the 326. 700 will require an adapter.

RoadRageDavid's '68 Firebird ran a "Level 10" 200-4R for threee years without issues, 500-plus HP, close to 600 lbs. of torque, clocked at least once at 200 MPH.

Either will deliver the OD you're looking for. Chevy guys "like" 700 better for obvious reasons. That's why there's so much more "info" out there about it.

Jim
 

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Sixt5 is correct. Not a PowerGlide. Suoer Turbine 300. No amount of modifications can make ST-300 "act" like a 'glide.

Drag racers use PowerGlide in LIGHT cars (under 3,000 lbs.) for best results in bracket racing. Often, 'glide cars are 1/8 mile "specialists". Only one shift... Heavier cars generally use TH400.

TH350 will literally bolt right in. Adding the lower 1st gear changes the entire "character" of the car. It will act similarly on the highway, but low-end performance is DRAMATICALLY improved, expecially when you have "tall" gears (3.23-higher ratio, lower "numerical").

If "originality" is not the primary concern, TH350 for a mild engine and TH400 (needs a bit of "adaption", but well worth it) for a "hot" motor...

FWIW

Jim
>>
I am restoring my '66 GTO Cv for concours competition, so originality is an issue for me. Could the TH200-4R or any other TH have been ordered factory or dealer-installed for my goat w/build date of the 4th week of May? Or were they really 'n truly not available til '67?

I have 3 motors I can put in, a 389 YF (360hp), a 389 YR(, both rebuilt, or a 421 YJ, and 2 Tripower units, both rebuilt. I know no 421s were factory installed, but I've read some were dealer-installed. The YR's DOB was 10/29/65; the YF was born on 08/23/66, and the YJ is a late '66 motor (356hp), as yet not rebuilt.

One Tripower intake manifold is original, dated 11/05/65

I will welcome opinions as to which configuration will work best in concours. I will use a RE ratio that will help the 2spd along, but I wonder if the 3.08 will serve just as well. Thanks for your help in this.
:willy:
 

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No TH 200 R-4's were available in anything until the 1980s. The TH400 was never available int he '66 year. Period. If you have an automatic '66 GTO, it came with an ST 300 2 speed. If you want to show the car as you say, follow the PHS and use the components that the car originally was built with. The best gear for a ST300 is a 3.23 or a 3.36. 3.08 is pretty tall with the lazy 1.76 first gear of the ST300 (Or is it 1.87...I forget....anyway, it's LAZY!)
 

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Thanks for your input. The tranny is original on the car. It has on the side these numbers: 66, then under that, it has MA 115.
 

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my tempest has the 2 speed st300 and ive been heavy on the gas on takeoffs and ive drove 15 miles from one twon to another going 100 mph right after raceing a lincoln truck with it wound past 120 and the transmission shifts smooth and never gives trouble, they may be lazy on takeoff but i beleave theme to be a very strong overbuilt tranny, jeep in mind these were put in gto's with alot more hp and torque so a 326 aint nothing for theme
 

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I have a two speed in my 65 tempest tied to a straight six. That combination makes for a very enjoyable highway cruise. And it is pretty easy on gas also. No burn out contests or 1/4 passes bit really nice.down the road. If the engine was a 326 and the rear in the low three I would mark it as a perfect highway drive combination.
 

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30 plus years ago, I bought an $800 '65 GTO with 64,000 miles on it and it was a 4bbl 2 speed car with a 3.23 open rear end. It would smoke the tire if you nailed it at 30-35mph and smoke it again on the 1-2 upshift at speed. (Bias ply 60 series Torque Twisters). I drove that car hard, and the trans never gave a hint of trouble. It was a great long distance cruiser car, too....75 mph all day long with decent fuel mileage. Sold it for $1100 about two years later and was excited about the $300 I made.....sigh....
 

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Thanks for your comments. I found out that MA stands for the ST-300 2spd and NA stands for the Superglide. Also found it was matched to my goat with a 3.23 RE. Yes, I recall the oh-so-lazy 1st gear. I always felt it was due only to the car's weight and to a 3.08 RE ratio.

Is it possible to perk it up with a custom converter? I need a good explanation of the "stall" speed factor, or a link, please. I could also change the RE ratio to improve response. The code on the axle housing is WE, which is supposed to stand for a RE ratio of 3.08, which made me believe I had a Superglide. Can anyone shed light on this conflict? The car has factory A/C and power brakes and steering; maybe w/all that it required a 3.23 RE?
 

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AC cars always had lower numerical rear ends. 3.08 is std. AC ratio for your year. Try the other forum (performance years) for your converter questions, but I'm betting you'll come up blank. Nobody runs these trannies for performance. My solution would be to pull the 2 speed, keep it, and bolt in a TH350. It's a straight bolt in, you can use your original shifter, and it will transform the car. Killer acceleration and great cruising still. A TH350 has something like a 2.75:1 first gear instead of a 1.77:1, and second gear is about 1.50 or so....still better than your current "low" range. It's a common, cheap swap, and worth the effort. JMHO........
 

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That's a good idea, thanks. I may just do that. And I will check out the PY forum. If it is so that no one has tried to perk this combo drive train, then I will be the first, no? If these 2spds are as strong as was said here, mebbe a posi and a tad better RE ratio will not hurt anything?
 

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Price to regear and upgrade to posi: $1500-$3000 if done by a shop. End result: a high revving, fuel guzzing car that sucks on the highway and is stll sluggish off the line.
Price for the TH350 upgrade: $100-$1500 End result: excellent cruising, excellent economy, long engine life, and jackrabbit acelleration off the line. This swap has been done thousands of times over the years, since the '60's. You decide.
 
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