Fuel??timing ??or both??

Did these problems start after the head gasket(s) was replaced?

Like one of the previous posters said, back to basics. Confirm the distributor is timed reasonably close. Then I'd suggest pulling the t/stat and run it without just to see if you have decent coolant flow - maybe you have a blockage. Even with a small radiator, I can't imagine an engine heating up that quick with a properly functioning cooling system. IF flow is good, then replace t/stat then find a way to verify temperature - second gauge, thermometer, etc- your gauge might be reading wrong. Also, check all carb settings on the bench, idle screws out 1 and 1/2 turns out from bottom out (2 or 4? Make sure they are all the same), secondary idle screw adjustment set right, accel pump not too tight, even float levels should be bench set. If carb was sitting with fuel in it, it wouldn't hurt to pull the bowls of and have a peek (gaskets are cheap). Make sure the gas in the tank is fresh too.

Once you get all these verified, then you should be able to at least keep the car running (maybe with a helpers foot on the pedal) long enough to do further diagnosis without fear of cooking the engine.