All engine regardless of age need heat to operate efficiently. when the engine heats up, pistons expand rings seat, etc. Think about it, why else would high performance engines like funny cars or pro stockers put heat into the engine before each run. Cars of the 60s, 70s, and up require engine heat just as todays cars do. I can't remember a car I built that didn't run around 185F. Granted 220F in a 1967 Chevy might be reason for alarm, but then cars weren't running 16 pound radiator caps either. As a kid 60 years ago we ran flatheads without thermostats and without radiator pressure caps. a lot has changed since then. My Gen 3 Hemi will be in the 195-220F range with a 16 pound cap and will will do just fine.
