I haven't been around long enough to know but I would suspect that when these fords rolled out of the dealership on a 90-100 degree day they didn't overheat. To me, that says that the original design was adequate for cooling. After 80 years of service, I can understand that things aren't working as good as they did back then. Hell, Henry had no idea that his vehicles would be around for 100 years. Overheating is a symptom of some other problem. Clogged radiator, worn out water pumps, water jackets full of crap. If these components were reconditioned back to the state that they were in when they were new there would be no problems. 90 degrees in 1935 is the same as 90 degrees today. My overheating problem originated in the distributor...solve the cause and not they symptom.