[riverat440]

You may want to try a flex fan or a pusher type electric fan in front of the radiator if you have room. The flex fan has thin blades with a heavy cup that flatten out at a higher RPM. The heavy cup moves much more air at an idle than a stock fan and when they flatten offer less resistence when you are moving when you don't need the fan. If the electric fan will fit you can wire it into switch in the cab to turn on manually or rig a thermostatic switch and a relay to make it automatic. Alot of imports had these mounted in their radiators so getting the parts aren't a problem but finding a place to mount it in the coolant may be.