1777CW 1963-1974 Inline 6 CW Rotation Riser 3 7/8" water pumpIf you are running a v belt with a riser set up (like a zips riser) and find you have heat cycling it might mean trapped air. The best solution is to build pressure to and the best tool is pump 1777CW. We designed an impeller with an increased vane count and a reduced impeller vane clearance to take build that pressure. It achieves greater flow rates, higher head pressure and a more efficient flow. The impeller color is due to Type II Class II