if y ou have a fan (or pair of them) that move enough cfm, and they are properyl installed in a shroud, you should not have any problems. many aftermarket electic fans especially the smaller ones (like 16" and under) don't move a whole lot of air.
you may not want and ford parts on your truck, but i have on on my '03 ford truck that i used to replace the mechanical fan. no problems with a/c sitting in traffic on a 105 degree day. i plan to use the same fan on my '59 chevy 36. it is a 2-speed fan that moves like 3,500 cfm on high.
