In order to increase your cooling system performance , you must maximize both the water flow and air flow. Using the proper pulleys and drive system is critical to matching water pump performance to your specific application. Race applications require a maximum water pump speed of 6,000 - 7,000 RPM.
For street applications, the water pump speed must at least match crankshaft RPM, to a maximum recommended 35% faster than crankshaft speed.
Twenty two years ago, I designed and built a water pump dyno. Then, I built a radiator fan and shroud dyno. I was privy to a lot of test equipment. So how do you figure cooling system at idle? I follow this simple formula: Let's say I am traveling 40 mph. The engine is turning 2000. The temp is 195-200. I figure my water pump speed and fan cfm. then I duplicated those numbers at idle. The silly thing thinks it's still going down the road at 40 mph. It works for me!
We also do not recommend the use of under drive pulleys on any application. Most water pumps consume minimal horsepower, except at high speed. Technically, there should be a variable speed drive on the water pump so when it consumes too much power at high speed and so it will reduce the water pump speed, but without a loss of GPH of coolant.
The two pictures below shows a 58'-62' Cad water pump. Note: the picture on the right shows the machine work necessary to install a unitized seal. This process is done on other makes of pumps also, in order to install a unitized seal. We also do this to 36' to 48' pumps.
We also do matching numbered pumps!
These 2 intakes show how the water lines go from back to front. A number 6 fitting at the back and a number 10(T-fitting) at the front, then they go to that tank that's in the upper left in the background (below). The tank has a thermostat housing with a thermostat. The small line at the left side of the tank is the thermostat by-pass line. It goes to the water pump and is used while the thermostat is closed. This manifold is for an FE ford. Any manifold can be configured this way.