I tried using the throttle knob as a cruse control on my 52, but it really was not worth the effort. I could see it only being useful on a long flat road, like the mid west. Here in VA e have to many hills to leave the throttle set in one place.
I now also think it could be a bad idea given the engine had no governor. If the transmission popped out of gear you will be searching wildly for the throttle knob or ignition switch.

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-