The Stovebolt Site Forums The Shop Area The Electrical Bay Overdrive Kick Down Switch With HEI Distributor.

Has anyone used a GM V-8 large cap distributor (with the coil in the cap) with an R-10 overdrive?
The normal application uses a wire from the KD switch to the neg side of the coil to interrupt the coil momentarily during the kick-down operation. How would one wire up the system using an HEI?
Fred

I have never tried it with o-drive but I have used a lot of test instruments that short out cylinders using the tach. connection. It has never damaged anything.

Thanks George,
After I posted this I took a good look at a spare HEI that I had.
The tach connector is also the coil minus terminal.
I installed an OD in a truck a few years ago that had a Pertronics conversion in it which seems to be wired in a similar fashion. It had a red wire from the module to the + terminal on the coil and the black wire to the - terminal. The KD operation worked fine on that application so it appears it should work on the HEI as well.
Fred

Use the "tach" connection in the cap as a grounding point, the one right beside the big power wire plug. It will momentarily kill the ignition to unload the gears so the OD can disengage, same as with a point-type distributor.
Jerry

Where were you guys 3 years ago when installed the overdrive in my Burb? Maybe I posted the question in the wrong forum. I couldn't get an answer or figure it out. Right now that wire is taped off inside the engine bay. As soon as I get back to my truck I'll follow Jerry's suggestion.

The problem I had was I couldn't find a way to mount the kickdown switch to the carb. The switch came with a bracket attached but no matter how many times I turned it over/around I couldn't get anything to line up on the carb. Now I have it mounted in the dash in one of the holes from the radio I removed. I hit it by hand and then let off the gas for a second to unload the gears. As long as you get back in the gas within a second or so it will engage in direct drive. If you hesitate too long it drops back into overdrive.

Anyway, thanks for clearing this up!!

Larry,
Presuming you have a V-8, there are so many carb options that it's unlikely to find a ready made KD bracket for your application.
I use a couple of small "L" brackets bolted together and mounted on the left front carb base bolt. Set it up so that the carb will engage the KD switch at WOT. It may take some trial and error to get it right. You may be able to modify the one you have.
Fred