# 2 speed powerglide, is it worth it?



## 67lemans67 (Feb 22, 2011)

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?


----------



## HP11 (Apr 11, 2009)

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'.


----------



## 67lemans67 (Feb 22, 2011)

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


----------



## SIXT5GTO (Mar 9, 2010)

*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


----------



## Mr. P-Body (Jan 20, 2011)

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


----------



## geeteeohguy (Feb 2, 2008)

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.


----------



## SIXT5GTO (Mar 9, 2010)

*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.


----------



## 67lemans67 (Feb 22, 2011)

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.


----------



## geeteeohguy (Feb 2, 2008)

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.


----------



## Mr. P-Body (Jan 20, 2011)

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


----------



## us66 (Feb 16, 2012)

Mr. P-Body said:


> 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.
> 
> ...


>>
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:


----------



## geeteeohguy (Feb 2, 2008)

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!)


----------



## us66 (Feb 16, 2012)

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.


----------



## danthepontiacman (Jul 5, 2008)

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


----------



## Jimmy The Greek (Aug 31, 2011)

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.


----------



## geeteeohguy (Feb 2, 2008)

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....


----------



## us66 (Feb 16, 2012)

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?


----------



## geeteeohguy (Feb 2, 2008)

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........


----------



## us66 (Feb 16, 2012)

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?


----------



## geeteeohguy (Feb 2, 2008)

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.


----------



## Thumpin455 (Feb 17, 2010)

There is a reason the ST300 isnt used in a performance application. It isnt a strength issue, its a gear ratio issue. Low gear in the two ST300 and PG is pretty close to second gear in the Th350/400, so everywhere you go it is sluggish like you are taking off in second every time. High gear is 1:1 in the two speeds and three speeds, so that is the same. To get the car to move ok, unless you are driving like grandma going to bingo, you will need more rear gear, that means higher RPM on the highway, more fuel consumption, and it will still be sluggish off the line.

Like Mr PBody said, the two speeds are used in light drag cars that have deep gears and high winding engines. That is not a good street combination unless you have a T bucket with a 7500 rpm engine and 4.56-5.13 gears. In a heavy car like a 65 GTO/LeMans it is going to be slower than driving a modern 4 cylinder pulling a small trailer.

For the best in drivability and mileage, put in a 2004R. I have run them behind 455s in the 4200lb 70 GTO with 2.93 gears and it still ran [email protected] They will hold up fine behind a 326. 

The 700R4 works but needs an adapter plate, I have one of those in the 70 GTO now, but it has been worked over with new heavier parts and a valve body that makes the TV cable much less of an issue. The adapter plate is thick enough and the yoke length of the 700 is different enough you will need a shorter driveshaft. That adds money to the swap. The 2004R and Th350 are near bolt in deals.

The overdrives get you lower cruise RPM and thus better mileage, they also have deeper first gear ratios than the Th350/400 so they come off the line better even with highway gears like a 2.93.

The Th350 is simple and easy to work on, bolts right in and gives you a deeper first gear so you dont have to floor it from a stoplight to not be run over by an Accord or a Hyundai. They are cheap and easy to find, and will hold up to far more than most people give them credit for.

My 65 LeMans has the St300 in it with a 326, and the 326 is going in my father in law's 65 GTO that I am rebuilding for him. The ST300 isnt going in it, instead it is getting one of the 2004R transmissions I have, or maybe a Th350. There is no way I would have a two speed in that car, and he will be 67 years old in May. He isnt a hotrodder, he just wants a nice cruiser, and the ST300 wold make the car feel like a slug even to him.

A custom converter for the ST300 is going to be more expensive than the rest simply because nobody does anything with them. Unless you leave it stock there is no reason to use the ST300. I swear we have this discussion twice a year here.


----------



## us66 (Feb 16, 2012)

Obviously, you're correct in that. However, I have to keep numbers matched, them that can be matched, at least.


----------



## us66 (Feb 16, 2012)

I agree with all that you said, but I cannot change the 2spd for concours competition, for which I'm trying to build. I'm trying to match up a '66 Cv w/every option I can find, but I would also like to perk it up a tad with a slightly better cam & roller lifters, RE ratio, and which I've heard are not usually inspected in concours, and by using the original 2spd. but improved tranny. If that's wrong, please let me know.

So I'm not looking for high speed, but only better torque. I may be locked-in to what I can do, but that's why I am asking - to find out. Thank you all for your help.


----------



## geeteeohguy (Feb 2, 2008)

If you're building for show, you can't have your cake and eat it too. Build it for show and be happy with it. The stock cam in your car already is superior for low end torque over any typical aftermarket roller set up. Ditto with heads. Your engine in stock form is going to have more torque than modified, unless you stroke it and go that route. Your best bet is to leave the engine and trans alone (if showing the car) and installing some stiffer gears in back. This will degrade its highway manners and fuel mileage, but will help off the line and around town, which sounds like your main priority. So: stock engine, stock trans, and 3.55 or 3.90 rear end ratio.


----------



## us66 (Feb 16, 2012)

Thanks, geeteeohguy, I tend to agree, for the most part. I have a reason why I'm trying to improve the car. Once, as I started my '85 C5 in a parade just after installing new aftermarket too-loud mufflers, the crowd cheered and clapped upon hearing what they (mustof) thought was a supergreat motor and car. Certainly, a '66 goat must sound as good as any other great car - doncha agree?

Now, a Tripower setup and a bumpstick with just a little more hair on it will provide a growl at idle and takeoff like there's a real tiger under the hood, I think.


----------



## geeteeohguy (Feb 2, 2008)

Tripower and Pontiac 068 cam is the way to go for your purpose. Great sound, slight lope, plenty of low end grunt. Melling makes the one you want.


----------



## danthepontiacman (Jul 5, 2008)

online forums say you cant use anything less then like a 3.55 gearing if you have od, they say it mess the transmission up, so how you get your 200r4 to work with such high gears? and if i may ask what kinda mpg it get?:cool


Thumpin455 said:


> There is a reason the ST300 isnt used in a performance application. It isnt a strength issue, its a gear ratio issue. Low gear in the two ST300 and PG is pretty close to second gear in the Th350/400, so everywhere you go it is sluggish like you are taking off in second every time. High gear is 1:1 in the two speeds and three speeds, so that is the same. To get the car to move ok, unless you are driving like grandma going to bingo, you will need more rear gear, that means higher RPM on the highway, more fuel consumption, and it will still be sluggish off the line.
> 
> Like Mr PBody said, the two speeds are used in light drag cars that have deep gears and high winding engines. That is not a good street combination unless you have a T bucket with a 7500 rpm engine and 4.56-5.13 gears. In a heavy car like a 65 GTO/LeMans it is going to be slower than driving a modern 4 cylinder pulling a small trailer.
> 
> ...


----------



## us66 (Feb 16, 2012)

More good information! I really appreciate your comments and the help you've given me on this matter. You've helped me make some important decisions I could not have as well as I can now. Thanks to all of you.


----------

