If you have the right radiator, good coolant flow and a good fan shroud you should run right at your thermostat temperature while cruising and in light traffic. Stop & go on a hot day I would not be concerned with 210, but 223 is pushing the upper range of normal a bit, IMO. Where is your temperature gauge sending unit located? What temperature thermostat are you running? Stock, mechanical fan or electric? If electric whose fan are you running, and what type of controls? OEM style radiator?