you just have to know what you're looking for, GoJeep has it done on his 4.0 and that's australia!
i think the mech. fan pulls 2000CFM but i wouldnt settle for less than 2500CFM myself due to cooling issues with the 4.0L http://www.jegs.com/webapp/wcs/stores/servlet/product_10001_10002_752006_-1_10117http://
that one is complete with a thermostat style switch that cuts on and off for you. for 125$ and 2800CFM 15" fan
EDIT: gojeep actually states 2000CFM minimum, 3000 for heavy towing/offroad use.
here's the article, there's also one beneath this on the home page a bout a 4500stock ford taurus fan :eek: bout to go read that next.
http://gojeep.willyshotrod.com/HowtoElectricFan.htm
what is cfm mean?