650 or 750 Edelbrock on 340
I'm not saying that yourself or others haven't had good luck with champion plugs, when I was a teenager they would foul out pretty quick. For my car's use autolite copper. For 2 cycle equipment, my lawnmower, quadrunner I only use NGK. My lawnmower is going on 11 years old and when I pull the plugs at the end of the season they look great. My equipment always starts right up and they run great.