I have been giving this some more thought. Since the spark plug broke off flush, and of course, broke off the porcelin as well, I'm thinking the only thing holding the rest of the porcelin in is the electrode. So here is what I have been thinking - spray some PB Blaster on the porcelin, let it soak in for a bit, apply some heat and then crank the motor and let the cylinder compression try and force the porcelin out, kind of like a cork. This would only leave the remaining threaded part easier to use an easy out on, plus no drilling. Think this is a good idea? It really can't cause any more damage, and the worse that could happen is that it won't work.
Comments and or suggestions?
Jim