I had constant overheating problems and have heard loads of remedies ranging from "the latest new super cool radiator" to "that stuff that supposedly runs 20 degrees cooler".
I bought 2 electric fans (one larger one smaller), a double pole 10 amp 12 volt relay, and an adjustable thermal switch. Remove the mech fan and shroud (gained the most horsepower of any mod I have done), and mounted the fans to the rad. Next I wired the output from the thermal switch ( which is supplied by a key operated source, in my case the cigarette lighter) to the coil voltage on the relay. tie the air conditioner fan power lead to the coil voltage too. run the fan positives straight from the battery individually on their own relay contacts, and poof, no more overheat, plus the ac kicks at idle! (make sure you get the polarity correct on those aftermarket fans so they are pulling)
do not use a ford starter relay, though they can handle the draw of both fans on one contact they are not made for continuous use and will promptly burn up!