1687CI 1975-1977 Inline 6 cylinder 250/4.1L 4 1/4" tall water pump

If you have the 1975-1977 Chevy truck with a 250/4.1L you might be finding it runs a little hotter now.  You might also find heat cycling is occurring with your riser set-up.  We designed a impeller with an increased vane count and a reduced impeller vane clearance to take care of both problem.  It achieves greater flow rates, higher head pressure and a more efficient flow and squeezes that air out of your riser casting. The impeller color is due to Type II Class II military grade surface coating which protects against corrosive fluids.  FlowKooler introduced the first hi flow pumps and continues to improve impeller design. Why is increased flow so important to cooling a hot 4.1L engine? Because it has been proven time and time again that reducing the cycle time between the heat source and the heat sink creates more opportunities to shed heat and drop engine temperatures. From 0-3,300 RPM…Nothing Beats a FlowKooler! General Specifications: Type of Material of Pump Body Iron Num