Hello, I'm an older guy (66) who has loved Pontiacs since I was 5 years old. I own a 55 Chieftain hardtop mild custom with a 57 "347" and just removed my old 55 B&M hydro-stick slant pan and am trying to shove a 700R-4 into it. Having fun but really in over my head. I wanted to post a question concerning water pumps however. I have the old style "gusher" system and my old pump has a "cast iron" impeller with blades that slant towards the left cylinder head. A friend wants to give me a new pump that has a "steel impeller" with vane blades that slant the opposite direction. Since both these hubs would turn in the same couner-clockwise direction as the crankshaft, why are there two different styles for my engine? Does anyone have any ideas if I can use this steel impeller pump without causing a coolant flow problem inside the timing cover housing? These pumps were used from 55-63 and no one has been able to answer my question. Thanks in advance for any input.