72 Dodge Demon Overheating

I have a 72 Dodge Demon with a 340 bored 30 over. It's got 10 1/2 to 1 pistons, holley stripped dominator intake highrise, running a 750 dual line holley. I have a 3 core radiator, 180 degree thermostat and I believe a high flow water pump and two fans, one mechanical and one electrical. I am still hitting 210 within about 1/2 hour with the car idling. Anybody have any ideas?