https://www.youtube.com/watch?v=Ug01EW7UZGM
Watch this video to understand the Model A cooling system. Lots of voodoo ideas out there that will only make your problem worse. If you are pinging, you are likely pulling your advance down too far. Keep lifting the spark handle a click or two until it doesn't ping. Not likely coolant getting INTO the combustion chamber, if it was that bad you would have steam out the exhaust. Tighten/retorque head often until no movement of head nuts. Let the coolant find its level, just make sure it stays just above the tubes. A restriction in the upper radiator hose (thermostat) will raise the pressure slightly in the engine block, therefore raising your boiling/flash point. Don't grind down the water pump impeller, turbulence in the coolant is a GOOD thing. Good Luck, don't jump to the worst conclusion, troubleshoot and diagnose first.