Carl, you are absolutely right, although I did say "assuming that the radiator is big enough to provide the required cooling."
Even in "Paulaskifield, Missouri" or the middle of the Mohave Desert, if you had a humongous radiator installed, the engine would operate at or very near the thermostat rating, and not overheat. Now if you lived somewhere that the ambient temperature was over 250F, then all bets are off. But then you wouldn't need to worry about your engine, because you'd probably expire first.
