[Michael C Henry]

Fe's large cylinders like temps at or above 180° I wouldn't go much above 190° . Once the coolant boils you have lost the control. Get the engine too hot and rings loose tension ,pistons and valves burn. Temperature is a balance more heat more performance and shorter life. I'm running a balanced type 180° hiflow thermostat. The big thermostat for Ford surge tank uses any Mopar thermostat. Ford has a thermostat with a large body and small opening valve. If the car is moving or a pair of fans are running I can keep it about there. I have a three position switch on the dash that I can manually turn on two or four fans. I also have two thermostic bulb sensors setting ontop of the radiator going to two adjustable thermostic switches that will automatically each turn on a pair of fans if it starts to get too hot as long as the master battery switch is on. The dash switch lets me get a head start if I know I'm getting into traffic or the like.
Temps like 160° would cause you to run a richer mixture and may cause the cylinder wall to get washed down. Carbon up and (or )fuel foul the plugs.