Pulley Diameters

Based on the page from post #21 if you have a 6.5" crank pulley on the engine, than a 5" pulley on the water pump would get you the 1.3:1 ratio Assuming my math is correct. (6.5 / 1.3 = 5)

My 67 273 (no AC) has about 6.125 crank and 6.5 water pump pulley, that is a 0.95:1 ratio (6.125 / 0.95 = 6.47)

Time to hit the wrecking yards!