I suggest you upgrade to a newer higher capacity radiator. Get rid of the clutch fan and go with a pusher dual fan setup with a thermo activated switch and a master switch to turn it on and off for river crossings ect. Run Royal purple radiator fluid with water wetter. Run Ams Oil in your engine this alone can see a 50 degree cooler engine. Go with a dual oil bypass system for the larger capacity. I am also sure someone makes a high flow water pump for your engine. Change out your old water pump. Who knows. It maybe filled with sedement and corrosion gunk which would reduce its ability to flow coolant. If you ever had a radiator leak and added a radiator stop leak this can kill the effectivness of your radiator.