My 318 magnum I went from the factory .086 quench distance to .038 made it ping a lot less as well as better MPG TQ and HP. That was the only change at that time, I even took it to LA and pulled a car up those big hills on my open trailer at sea leval and no pinging on 87 octane california crap gas. After that experiment I am a big fan of maximizing quench area and minimizing quench distance.