The Stovebolt Site Forums The Shop Area The HiPo Shop th400 kickdown in an AD

I have a modified Task Force era gas pedal and linkage for operating the quadrajet on a 350 engine in my 1949 3100.
I also have a TH400 transmission and I am looking for a way to rig the kickdown switch. It is the rectangular looking one with the round rod that sticks out and pushing on it slides the switch on and off.
Anyone have any ideas as to how rig this switch to operate when I mash the gas pedal to down shift to 2nd gear?
Carl

Some of the early T400's used a switch mounted to the carburetor, and the secondary linkage triggered it, Pontiac was one of them. The later cars used a switch under the dash activated by the throttle lever. Yours is the under dash type activated by the throttle lever, it's not water proof, so don't mount it under the hood.

Thanks Joe! Back to the drawing board. I need a carb mounted one. Any idea where I should start looking?

Try a micro-switch- - - -lots of them on Ebay. I prefer the ones with a small roller on the end of the switch arm. They're waterproof and very rugged- - - -and all you need is a momentary contact switch to trigger the solenoid inside the transmission.
Jerry

Any type of micro or push button will work, just be sure it's water proof. The trans switch doesn't draw many amps, so heavy duty is not really needed. Here are lots of photos to look at, https://www.google.com/search?q=tur...HbVdB_gQsAQIMA&biw=1514&bih=1017

I may have one laying around, I will dig around tomorrow and see if I can find one.

Mod supplied bracket or make a bracket and mount this micro switch (or equivalent) anywhere on carb that it's paddle is depressed by throttle linkage at 90% mechanical WOT.

Another option.

Non slider, Real deal Pontiac/Buick style per Joe.

I like this type- - - -it's a little more rugged than the mini-micro pictured above. It has normally-open and normally-closed contacts, also.

http://i.ebayimg.com/images/i/281563458468-0-1/s-l1000.jpg

Jerry

I also have a turbo 400 auto mated to a 283 w/600 Holly. My transmission will shift normally from stop to speed limit, when I need some boost I just manually shift from drive into second and back when the need arrises, is this the same thing in essence as using the kickdown cable?

A TH 400 has an electric kickdown- - - -not a cable. The TH 350 has a kickdown band that applies only if the cable is used, but I think the 400 works the same way with the manual valve as it does with the switch.
Jerry

The only problem with manually down shifting when you need to "get on it" is that you risk dropping the transmission lever too far and into low gear instead of 2nd gear.

summit sells microswitches that also have mounts for carbs, but they are not cheap. Some vehicles used a switch under the gas pedal, which I think is a more robust setup.