Originally Posted by runn141
i have a water pump pulley that is the same diameter as the crank pulley making it 1:1 ratio. looking at it, it may be just a tiny bit bigger than the crank pulley. will this be ok for the street on a sbc? or will i need the pump turning faster?
A lot depends on the rest of the cooling system and the engine specs like compression, fuel used, timing, cam specs, etc, as well as the vehicle use, gear ratio, and other factors that have an effect on engine cooling.
If the engine is in proper tune, and everything to do w/the cooling system (fan, airflow through the radiator, thermostat, shroud, fitment of the fan to the shroud, etc.) are all in sync, you might get by w/a 1:1 ratio just fine. Generally, passenger cars cam w/something in the 1.3:1 ratio (water pump over driven), so you'll need to do some testing to see what your requirements are. AC will require more cooling capacity, all else being equal.