SPARKPLUG SUPER-HEATED AND MELTED LONGITUDINALLY DESTROYING THE OUTERMOST SPARKPLUG THREADS (7 THROUGH THE SEATING SURFACE OF THE SPARK PLUG). INNER MOST THREADS, THE ONES DEEPEST INTO THE HEAD WERE NOT DAMAGED. A SECOND PLUG WAS INSTALLED ALONG WITH A NEW SPARK PLUG WIRE AND WITHIN 20 MILES, THE SPARKPLUG WAS AGAIN MELTED BEYOND SALVAGE AND THE NEW WIRE BURNED UP. DUE TO THE DESTRUCTION OF THE SPARKPLUG, IT WAS ABLE TO BE REMOVED WITHOUT TOOLS AS THERE WERE NO THREADS REMAINING IN THE CYLINDER HEAD. FORTUNATELY THE FIRE DAMAGE (LIKELY FROM THE SPARK OF THE PLUG) WAS LIMITED ONLY TO DAMAGING THE SPARKPLUG AND THE SPARK PLUG WIRE LABLED #3. *TT