[jal]

All,
Hoping someone can possibly help me out with some tranny info. Purchased a 64 Tempest ragtop for my wife recently with the 215 straight six. The tranny is a 2-speed automatic that I'm trying to ID. There are no cooling lines and, as I understand it, is air cooled based on the factory holes/openings I see in the bell housing. This car could really use a TH350 with a decent 1st gear vs the 1st gear in this 2-speed to get it going from a stop.

My question is, (I can get under the car and get some measurements) does anyone know what actual tranny came in the car from the factory and, is a TH350 a direct swap using the same cross member and driveshaft? And also curious what the tranny bolt pattern is on this 215, however, I can also grab some measurements to get that figured out if no one is quite sure.

Any info is greatly appreciated!
Thanks,

-joe

[tempest1964]

I believe the factory 2 speed automatic is called a SuperTurbine300, or ST300 for short. It is often mistaken for a power glide, they are not the same. The turbo 350 is supposed to be a direct fit as far as the crossmember and the driveshaft length. Others with more knowledge than I will surely add more info.

[Jeff Hamlin]

It is the air-cooled ST300.
It should have holes in the Bell area and the Tourqe Convertor will have cooling fins and sort of resembles a turbine.
I know the 350 will bolt up with the OHC 6 but not 100% sure about the Pontolet 6.

[John V.]

The Buick Super Turbine was used to back the Chevy produced 215 straight 6 in '64.

However, the Chevy Powerglide was also used behind the '64 215.

Both were air cooled. The Master Parts Catalog (MPC) outlines the differences between the two, without looking it up my recollection is a difference in Torque Converter was among the most significant differences.

The '64 Tempest Inspector's Guide also noted a Secondary Trans Code whenever the Powerglide was used in lieu of the Super Turbine.

The Final Assembly Plant was supposed to stamp the numeral "1" after the Engine Plant stamped Engine Code already on the block.

Bottom line, your Tempest could have been built with either of these two automatics.

I believe there is a nameplate on the original trans that would have the tranny part no. or other info that I believe can be used to identify which one you have.

I'd have to check the '64 Tempest Shop Manual to confirm that there was a nameplate attached to the auto trans.

If you are going under the car, look for the nameplate. I'm guessing if it is there, it is on the passenger (RH) side.

Post any nos. you see and I'll be happy to look the p/n up in the MPC.

My understanding is a TH350 is the easiest swap. Never done it but you can probably search this forum and find some threads about such a swap.

Personally, if you're keeping the 215, I'd keep the 2 speed. Mostly cause I think originality is cool but I understand the drag racers loved the single shift too!

[b-man]

The TH350 is a direct swap. Driveshaft, crossmember location and shift linkage all line up and work without modifications. My ‘64 Tempest was a 215/2-speed with air cooled ST300, the Powerglide isn’t that common in these cars from the ones I’ve seen.

The factory trans cooling lines also fit directly, you’re going to need some for the TH350.

[jal]

Guys,
Really appreciate all the information and help on this question. Car runs great but really needs that decent 1st gear to get moving so, will plan on this swap. Yep, already knew I'd need to run cooling lines for the TH350. So, I guess all I'll really need will be a converter for the swap unless the original is a possibility. I'm figuring no but, a typical converter should be easy enough to find.

Thanks again guys,

-joe

[b-man]

No go on the converter interchange.

The ST300 will take the same converter as a TH350 or TH400 but your air cooled converter really isn’t compatible plus the stall speed is tailored to the tall 1.76 low gear of the 2-speed as compared to the 2.52 low in a TH350.

Plenty of rebuilt stock 12” TH350 converters are still available for a very reasonable outlay.

When I was driving my 215/2-speed Tempest it wouldn’t automatically shift out of low until 70 mph under full throttle. It was a smooth and fairly economical combo, returning 20 mpg overall. It ran the quarter mile in just over 20 seconds at 70 mph, running the entire quarter mile in low gear. Mine had a 2.56 rear gear, pretty sure the majority of them with that engine/trans combo were equipped the same.

[Sirrotica]

Originally Posted by jal

Guys,
Really appreciate all the information and help on this question. Car runs great but really needs that decent 1st gear to get moving so, will plan on this swap. Yep, already knew I'd need to run cooling lines for the TH350. So, I guess all I'll really need will be a converter for the swap unless the original is a possibility. I'm figuring no but, a typical converter should be easy enough to find.

Thanks again guys,

-joe

Many years ago I had a 67 Lemans with a 326, and the ST 300, W/2.56 axle. The transmission went south, and I replaced it with a long tail T400 out of a 68 full size car. That was just what that combo needed was a lower first gear, it made the car a much better daily driver with the extra lower first gear.

The car was eventually made into a dirt track car, it's pictured second in my signature pics. Ended up with a 400 CI/T400 and a 3.55 posi rear axle, a clone GTO race car.