The "TS" suffix indicates "Tapered Seat"- - - -no gasket. That's definitely wrong. The too-short thread of the Champion plug will interfere with proper heat transfer from the plug to the head, also bad news, plus exposing some of the threads in the head to combustion gases will deteriorate them in a hurry. Better come up with either the right AC plug, or at least a correct thread length and heat range in a different brand.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!