1899 2001-2007 496 8.1L Chevy GMC water pumpIf you're hauling weight and there is limited airflow your big 496 8. 1L might just start running hot. Flowkooler has a solution. FlowKooler designed a high flow water pump for the 496ci block with a CNC machined billet impeller. It has an increased vane count and a reduced impeller vane clearance to the volute. It achieves greater flow rates, higher head pressure and a more efficient flow. The impeller color is due to Type II Class II military grade