I have a 1948 1 ton chev panel with a 235 engine from 1958-1962. It also has a 457 rear end. I put on a tac to see what rpms I am running. At 45mph I turn 1400 rpms-at 50 mph I turn 1800 and at 55mph 2000 rpms. I still have some left but I think I am close to top end. Does this sound right and at what speed or rpms should I run this engine.
