I am thinking the stock fan is 2000 CFM, that sticks in my head anyway. I posted the link to the Hayden fans but there are others out there that pull far more air. With 2 16" fans it should be around 3600 CFM and can be varied with the newer controllers.
Then putting on a supplemental for the AC should be fine. I just can't see wasting all the energy on a mechanical fan that is useless at 60MPH
http://www.haydenauto.com/upload/Hay...hure_Flyer.pdf