1965 289cu running hot

Well, if the temp stays normal when driving, then the radiator is large enough, if the temp creeps up when idling, then there is not enough air flow through the radiator from the fan on the water pump, a fan shroud helps it should be as close to the radiator as possible, and the fan blades should be in the shroud 50% of the way if possible, some of the narrow shrouds will not allow it, more blades on the fan helps, if you have a thermostatic fan clutch on the water pump for the fan, it could be bad, if it is then it will be free wheeling instead of pulling much air through the radiator. Put a valve on the heater hose coming off the intake to the heater, and during the summer shut it off, any coolant going to the heater is not cooled by the radiator, so if you don't need the heater, then stopping the coolant going to, it will force it to radiator to be cooled. The hotter the thermostat the more efficient the radiator is, so if you put a 160 in thinking it will cool better, it actually isn't, put a 180 in it, or a 195. Good Luck.