running hot

72 mgb with new radiator, new water pump, new 165degree thermostat, great engine compression, timing is good runs temp well beyond "n" at highway speeds and after much intown driving. any ideas? ????head gasket

Are all the hood and radiator seals in place? Did you replace the radiator hoses? Did you replace the radiator cap? Do you have the correct sending unit? Have you used an infrared thermometer to verify running temp? Have you checked the coolant level? Are you losing coolant? Is the thermostat installed right side up?
165 degree thermostat is on the cold side and probably won't close allowing coolant to cool in the radiator. Have you done a compression check? Do you have white smoke coming out of the tail pipe?