Cooling issues

I have a 69 Dart with a 383. I am running a Cold Case radiator, 22", with the factory shroud, and a flex fan. It has a 180 thermostat, and it barely runs 180 on a hot summer day in Phoenix AZ. If I stop at a light, it might get to 190-195, but it cools right back down. I did have a problem when I first got it running. Changed the water pump to a Milodon high flow, and put a different high flow thermostat in it (it would get to 250 and puke before). The shroud helped keep it from heating up too fast at a stop.