Classic/Antique Car Repair: Best Coolant for 1939 Buick

Question
I have a 1939 Buick

New radiator, rebuilt engine, 160 Degree Thermostat. Using 50/50 mix of water and conventional antifreeze

Engine settles at 185-190 degrees - seems high

What is the best coolant for a car from this era?

Answer
The 160 is the recomended one for that engine. I would use the green prestone or any of the plain general purpose perminent anti freezes. I would not be concerbered with temperature readings that you have as long as you are running the 50/50 MIX as its boiling point is 245 and if you are running a pressure radiator cap the boing point is about 300degrees.