[Tinker]

Vacuum leaks, timing, carb settings, all will all effect vacuum reads... or am I wrong. Low readings doesn't mean major engine problems but maybe a tuning issue. If you have blowby or low compression readings, then yes.

Flatheads always run hot when retarded. When is it too much advance? and when does it hurt performance? and what is to say that the dizzy is setup right too? Do point gaps effect advance settings? Inquiring minds want to know.

Lean condition will also cause a flathead to overheat too. Well a host of things will.