That tip makes sense, a newspaper is better than a hand. I hope that my overheating was because the fan wasn't locking up like it should and was not pulling enough air through the radiator. I think that is consistent with the fact that I didn't overheat when driving at highway speeds on flat ground and it cooled down fairly fast when I pulled over on a hill. On hills I'm normally driving slower and the engine is working harder.

Yes, if you are over heating this is the easiest way to eliminate the fan not locking completely, it's like a torque converter on your gearbox not locking. I like thermostat fans as they can run independently of engine speed. But in the 70's this was the solution. If Santa wants to get you a Holley EFI they have the ability to run a dual coolant fans thru a GM relay as well as the other benefits of fuel injection.