I have the stock radiator and use 2 of these fans. It's the 12" Mr. Gasket fan Part #720-1986. They are 1400 cfm each. Only $69 each. Worked great all last summer even on the hot & humid days. Some people run with just one fan but there is 2 there for a reason. I refused to run just 1.
http://www.jegs.com/webapp/wcs/store...tegoryId=13441