Edelbrock 8856 Engine Water Pump, multi, one size

A bit on the pricey side, but this water pump feels like a quality unit and works well. As with pretty much all water pumps for Pontiac engines of this era, you will want to use a hammer to minimize the gap between the supplied divider plate and the impeller to achieve maximum pumping efficiency. From the factory, there is a sizeable gap present, but it is easily and quickly minimized by using a hammer to shape the divider plate. Otherwise, installation was easy. In my case, I replaced numerous other cooling system parts, so I can’t speak to any cooling improvements that are the direct result of installing this water pump alone. My ’66 GTO does run cooler, but that could also be because I installed a fan shroud, replaced the fan clutch, and replaced the thermostat in addition to the new water pump.On the whole, it’s a good water pump and one that I recommend. It’s also significantly lighter than the standard cast iron water pumps, too, so that’s another bonus.