The Stovebolt Site Forums The Shop Area The HiPo Shop Variable Speed Torque Converters

Ive just recieved some info about variable speed ( 2 speeds) torque convrters that are GM OEM. Apparently they have been used behind big caddy motors with success. Should anyone want a copy let me know.

Is that the same thing as the 'switch pitch' units used in some '60s pontiacs?

chip

Thats the ones. Will use correct terminology next time chip. Need a copy of the info? Email me or send a PM and Id be more then happy to oblige. Have a nice day.

Similar to my 55 Buick DynoFlow?

Here's a link to some of the info I have found and been sent. Are these thhe same sort of thing Ken?

Nope . . . different, the older buicks have a continuously variable pitch converter. Engine revs stay the same speed while cruising and the car continues to accelerate.

I ran one of the switch-pitch converters in the turbo 400 for years when I was racing. I used a manual switch hooked to the shift lever. Used to launch in the high side and switch as soon as my foot hit the floor. They were a little slow in switching so right before it would hit second gear the converter was almost locked up. The old car would run about two mph faster with the S-P than a stock 400 converter. GM had two different models, one was a little looser and wouldn't tighten up as much. I don't remeber what cars came with which one, but we tried both. Kept blowing the looser ones apart!

I have heard Dodge is working on a new model for some future truck. They are great for gas milage. The big advantage is you can run a low gear like 2.91 or so and still have power. That was the original idea from GM, they could get big heavy cars with low gears rolling easyer. Most I believe were switched by the acclerator peddle. I just finished some work on a 67 442 Olds that had one. It switched from the peddle linkage, about 3/4's throttle it would go into the loose side. Joe

Joe H

A friend of mine, hooked on Oldsmobiles, said these SP units were real nice to use. And, dunno if it's correct or not, they were available only up to 1967. He had some,if not mistaken, but in 2 spd trannies, Jetway I guess.

Are the S-Ps still in production? What stall speeds are available?
I've got a TH-400 long tail BOP, where would I find the parts to convert it to a S-P tranny?

Thanks, Chip

Clip in one of my posts above is a link to some helpful info. I think it changes the stall speed from 1800 - 2600/2800 if I remember. I have a guy in Cali looking in the junk yards for some of these trannys and will post prices etc when we find some. In the link above is also a contact for some guys building these up. Hope this is of some help.

The only difference from stock 400's were the pump, output shaft, switch on the valve body, and converter. We would switch them around all the time looking for more power. Check the junkyards for 65 thru 67 Olds, Buicks, Cady's. All would be big cars except the Oldsmobiles. They used them in the 2 speeds in the small cars as well as the big sleds.

You might check with a local transmission supply house. Here in Kansas City, MO and Wichita, KS ( A & Reds Transmission Parts ) E-Mail [email protected] had most of what was needed to convert a standard over to S-P. They cut a converter apart for us so we could see what failed and how they work. Joe