1686 1978-1989 Chevy GMC Inline 6 cylinder 292/4.8L 3-15/16" tall water pumpIf you have the 1978 1989 Chevy truck with a 292 4. 8L 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