A friend of mine drove Nascar trucks andand in Nationwide, he explained to me they test plugs to see what gives them the most power. They start off with a .030 gap and work up from there on a dyno. He would not tell me what gap they found to have have the best power but he did tell me the Champion plugs came out on top. We tested plugs on our Leitch race engine and 604 but we didn't have the budget that Nascar teams have so it was a much shorter testing session. But we are running on pump gas unlike a 3000hp engine