While we're discussing this, you might consider using Redline Water Wetter. It is a surfactant that cuts the surface tension of the coolant between the engine block and between the coolant and the radiator tubes.
This allows the coolant to transfer heat much more efficiently from the engine to the radiator. With pure water and no antifreeze , it will lower your operating temps by 15-20 degrees. With antifreeze its much less effective but can still lower temps by 5-10 degrees.
This might sound like snake oil but racers use it on the track. It was recommended to me by a friend who builds race engines and dragsters and races them himself. I'm going to use it in Ol' Roy and The Bismarck this summer.
