Duster 383 cooling issue

I have a 74 duster with a 383 60 over stroked. I am having cooling issues it has the 26in radiator with a 180 stat and a 165 stat relay serpentine setup with dual electric fans runs great and stays at 180 when parked but after driving for about 20 min it jumps to 220 and will not cool back off and wants to climb higher. any tips. IMG_3100.jpg IMG_3112.PNG IMG_3032.PNG