Bro. Greg,Just another point of interest. Just got back from a 20 mile jaunt, mostly at 60 MPH. With the outside temp at 91* I was running a constant 185 degrees with a 160 degree thermostat and a "stock" Cu/Brass 4 row radiator. Running 34 degrees total mechanical advance at 3000 RPM (60 = 3000) and NO vacuum advance involved.
When I came back to city streets and switched on the vacuum advance The twin 16 inch fans held the temperature to 195* but at idle at a stop light the temp went up to 200* and stayed there.