In my engineering school days, I drove a 58 Chevy Del Ray, the bare-bones 2 door sedan with a 235, 3 on the tree, a 3.70:1 rear end, and 14" wheels. That car saw speeds of 65-70 MPH every day, and running mid to high 80's when we had a 75 MPH interstate sped limit in Tennessee was not uncommon. The engine will run that fast, but pickups from the 50's and 60's were built to work for a living, not keep uip with traffic on the autobahn!
Jerry