I worked for a truck leasing co. in the early 60,s. We had a 58 Chevy pickup with 6 cyl. engine for a service truck. I had a service call near Wichita, about 180 miles from KC. The Kansas turnpike had recently opened & the speed limit was 80 MPH. I was dog tired after working all night & day. I put the foot feed to the floor all the way back. It did 80 downhill & 75 up hill. I figured I would get home or go to sleep when it blowed. It ran for many more years after that.
George