[kingkobra]

Wizard's comments were exactly what I was getting at in my original post.

Thanks for all the responses and links. They've been helpful.

Unfortunately, the question I posed doesn't have all the information needed to make anything other than a general response, which was what I am looking for.

Truly, to make a decsion I first need to find the worst case heat rejection requirements for my engine. Then I can calculate the necessary coolant flow to meet the cooling requirements. Next I need the pump curves for the pumps I am considering and the pulley diameters for all the pulleys in the considered belt drives. From there exact (theoretical) hp and flows could be calculated.

The problem I am having is that the information needed for the required calculations has proved difficult for me to find. So I am looking for rule-of-thumb type responses from experiences with various water pumps on 5.0L (mostly stock) Mustang engines in Cobra kit machines for street use.