Leave the coolant and oil in the engine. I agree with advancing the timing to cause it to detonate, over-rev the engine, cut the exhaust off, and let it blow. The exhaust sounds cool to the spectators. The detonation is like pounding on the piston with a sledge hammer. Either the cast piston will fall apart, or a rod will let go. Too high of RPM will speed up the process. Also, I have seen people put junk push rods in the pan positioned so that the crank will hit them and make a knocking sound, but not cause the engine to break. This makes for a good show.
Phil
