The "kick down" switch for my 67 turbo 400 is mounted to the accelerator linkage rod going to the carb. If I adjust the rod to where it just slides into the carb linkage sometimes it doesn't return all the way to idle. If I try to adjust it to leave a little slack it "preloads" the kickdown and causes the trans to shift sooner.
What is the correct way to adjust it?

 

That'll be in the service manual.

My Toromado had double switches on the underhood accelerator linkage--one for kickdown, another for torque converter pitch. I scrapped the OEM switches for a gas-pedal mounted kickdown, and an electronic box for torque converter.