The problem comes when you try to remove a spark plug from a reducer insert. If the insert comes out with the plug you'll have a devil of a time getting the plug out of the insert without damaging the threads of the insert. Been there, done that. So you want the insert pretty much permanently set in the cylinder head. The anti sieze on the spark plug definately makes life a lot better, but you still want that insert rock solid. I tried the Red Locktite route. It did not work as well as I hoped. called Terry at CH to see what they were using. Tat's where I got my JB Weld information and experience. It worked.