The Stovebolt Site Forums The Shop Area General Truck Talk throttle knob on the dash

I do know a guy that has a '72 C20 that has a throttle knob in it. Stangely, it's also an automatic.
Like red58 said, it's mainly for PTO work. I do use mine during warm up to keep the rpm up, but not for a cruise control. That's not only dangerous, but illeagal in most states.