antifreeze percentage?

63 dart 360 stock car. what should I use for coolant? racing will be in warm months from april to september. I may or may not drain the system when it gets cold depending on what you guys say if we go with no antifreeze. I had heard that distilled water is preferred & iirc? there was something about ionized water being better thank that but this might be my OCD acting up. and there was something about using a can of antirust/water pump lube when antifreeze ain't required. not using a thermostat. what say you guys and thank you for your time. RR