Do any old Pontiac guys know the answer to this question concering the 4 bolt water pumps used from 1955 to 1963? It seems there are two configurations, one is a cast iron impeller with curved vanes to the direction of the left cylinder head (when sitting in the driver's seat) and one that has a steel impeller that has vanes that curve the opposite direction. Since my 1957 "347" has the older style cooling system where the heads were cooled first through long perforated tubes in the cyl. head water jackets, it seems it would be important to know which direction the water should initially be distributed based on the impeller's vane curvature and the fact that the left inlet is higher than the right side. The reason for the two pumps is probably due to accessories that might cause the drive belt to run the pump pulley clockwise rather than counterclockwise like the crankshaft turns. I would sure appreciate any knowledge on this as I can't seem to get an answer from Kanter, Ames, or anyone else that sells old Pontiac parts. They acknowledge the existance of both configurations, but can't give me an answer to which direction the pump should spin for a car with the only accessory being an alternator which spins in the same direction as the crank. I would assume it would be the cast iron impeller vanes that curve to the left head first, but I have had cooling issues when stuck in traffic with this pump (all other possibilites corrected) and wonder if I have had the wrong pump the whole time. Any experience with this question would be greatly appreciated.