I wondered what you recalled from personal experience, or if you ever run a test, say using one or two dash 5 plugs with the regular 46's, running the engine, looking at the color and feeling the temperature difference just in your hand... Unless you could have access to a tempersture probe to really see what the difference is... That might be the only way to go, since plugs get very hot, and hot is hot in your hand!..;)
