help with over heating

Are you running 257 degrees? If not, you ain't overheating. With a 15 pound cap, the boiling point of WATER is raised to 257. Coolant even higher. First thing you need to do is ditch that thermostat. Put either a 180 or 195 in it. With a 165, you may as well not even run a thermostat because it's open all the frikkin time. The water aint even stayin in the radiator long enough to cool off.