There are many possible solutions, you will need to experiment to see which work for you. I assume your overheat issue is when driving between plow jobs and not when actually plowing a driveway, if I am wrong please let us know. Make certain you have proper coolant mixture and fluid level. Use a shroud around your engine fan. Switch to a fan with more blades, but not a flex fan style as they do not move enough air at slow speeds. You can add an electric fan in front of your radiator to push air into it. Try positioning the blade differently to allow better air flow. You could also try replacing the radiator with a larger radiator with greater core thickness. Even though your engine might not require a 4 core radiator the situation you have with your plow might dictate otherwise. Not knowing what type of Jeep you have you could also add louvers to the hood to allow hot air to escape, CJ's are notorious for poor air flow out of the engine compartment.