I would respectfully disagree. My first Mopar was a 1971 Charger, that I had transplanted a 340 into. I kept getting a misfire, and would change the plugs out, using the same factory recommended Champion plugs. The misfire always found it's way back. So, having a friend who was a mechanic, I went to him for advice. The first question he asked was if I was using Champion plugs. When I answered to the affirmative, he suggested that I changed to Autolite plugs. Never had another misfire after that.
Maybe it's just my luck, but I've never had good luck with Champion plugs, no matter what the application was. Just sayin'.