Dart Running Hot?

I have a 65 dart with a 360 in it and it always ran 210-212 with the old radiator and the new one i put in thinking the old one was shot. I tried several part store thermostats and water pumps to try and get the temp down with no luck at all. even tried water wetter and no change. I finally fixed it when I bought a flowcooler water pump and Mr gasket 180 thermostat from summit racing , the temp runs 173 on really really cold days otherwise it runs 180-185 highway, and might get up to 200 if i sit in traffic for a long time with out moving. Part store thermostats are junk, they don't flow enough volume.