Im having trouble with my Chev 305 running too warm. I have a shrouded DaviesCraig 16inch thermo fan on there at the moment, but that's not able to keep the motor cool (was a bit warm in Adelaide recently). It seems it just can't flow enough air. So I've purchased a WB clutch fan and shroud to suit. The only thing I'm not sure of is if the water pump pulley is the right size or not (affects the flow rate through the radiator). What diameter did water pump pulleys come from factory for the SBC?

PS I've done all the other stuff to the cooling system so I know its only the thermo fan. Car runs just fine in moving traffic, just not when standing still.

Thanks muchly,

Pete