Hi Bob...sorry but you've confused me. The tapped hole is in fact a coolant drain for the block. Are you filling the engine via the radiator? Or do you have the upper hose removed and are you pouring coolant in that way? If you're adding coolant through the radiator, I'd expect it to begin coming out of the engine coolant drain hole as the level increases (from bottom up)...remember the thermostat will be closed if the engine is closed and the thermostat is working as it should.
Jon
