Yes, necromancer is right. I was just pulling your leg.
When you break the porcelain out of the plug, wear safety goggles. That sh*t LOVES to go straight for your eyes! Ask me how I know
. The problem is, there's not much meat on the sparkplug, once you bust out the porcelain, so it may be difficult to tap it to a size of an available bolt. I made mine, by mig welding a 3/8ths nut on the outer end of the plug, then cut a piece of 3/8ths all-thread (app. 3 inches long), threaded it into the welded nut, then threaded another 3/8ths nut over the all-thread, to act as a locker (once you adjust the all-thread the way you want it). It's worked for me for over 10 years and only cost me about 2 dollars and took 15 minutes to make.