How to pick an electric fan?

I am needing some help in deciding how to size and select the proper electric fan for a street car. Does anyone have any expertise in this area, or know of any good articles to find the required cfm that is needed? I am not having much luck. My car is a 75 duster, 416 stroker, eddy heads and air gap intake, tti headers, northern aluminum radiator, standard water pump. The radiator measures 20.5 inches wide, 17 inches tall, and no more than 3 inches from radiator to water pump pulley. I need a puller, as I have my transmission cooler mounted on the front of the radiator. Any help would be GREATLY appreciated.

Thanks,

Will