Ideal to prevent overheating in street rods and street machines, as well as in tow rigs and motorhomes. Using state-of-the-art racing technology, Edelbrock has designed these "super cooling" Water Pumps to provide maximum flow, maximum pressure and equal distribution to both sides of the block with in 1%. Available for most popular applications, these high performance pumps flow in only one direction for optimum efficiency. The casting's computer-designed internal passages and precision powdered metal impeller produce the maximum flow rate possible. 5/8 in. Pilot Shaft. 7.9375 in. From Block Surface To Hub.