Wow, with all of that on your cooling system you should not be running 210... even in hot temps....
2 Electric fans, shroud, 3-row, and 160 stat?
That is way too high for all that cooling hardware. Something has to be going on inside to cause that engine temp....
2 things.....
Check the timing very carefully.... and check the choke too... run the car and let it get really warm.... turn on the AC and watch the choke plate on the carb, let the car do in the driveway what it does on the street.
You did not mention what carb you are running, but on most carbs with the choke all the way open there is a detent that drops the RPM range to it's lowest point on wide open choke, you can even flop the lever open all the way yourself, see if the engine drops to the RPM range you are experiencing.... if you find that it is too low, adjust the throttle speed screw a tad higher to get more on the bottom end, then you might have to back off the fast idle screw a tad to compensate. there is a fine balance between these two screws and it took me a long time to find the "Happy" place with them both.
If your timing is off the car will run warm too, make sure you are on....
And my last 2 cents, in some cases a cracked head will exhibit this sign, when the car is cool or even warm the crack does not meak too much vacume, once the car gets really hot the crack opens more and more until a drop in vacume causes the car to idle down and run a little rough.
