Water pump GPM?

I was thinking about using an electric water pump on my 440 also. I still have the stock pump on the car and have not went any further. Your concern about the reliability of an electric pump should be answered by the pump manufacture. Call the companies that make the pumps and ask to speak to a design engineer. He should be able to answer your question as to " How reliable the pump will perform on an extended drives" . You might want to ask about using a thermostat as well. Some pumps will need a small amount od back pressure to prevent cavitation. Taking the thermostat out of a engine to increase flow usually results in higher temps in the engine since the pumps is not operating properly. Many racers use a washer with a 1/2 hole as a thermostate.