Fan CFM

You want the widest one that fits over your cooling tubes,I highly suggest twins fans with flaps in the shroud that holds themif you have the $$, You want a puller NOT PUSHER, as for cfm's the more the better but search for one that has an amp draw under 12 I know summit has there brand fans around 3000 cfm,s and only pulling 8 amps or so !
also, straight blades not curved!