If it does ping you could try a colder plug, as stated previously. I always ran a #85, I see though now the listing at the parts store is an #86 which is hotter. Maybe you got the hottest plug they make for that ap. I know that an autolite #86 is the hottest version of that plug. I can't believe that NGK doesn't have a number on their plugs, that's got to be the dumbest thing a plug company could do.