its funny because in the edelbrock heads they recommend a champion rc12yc plug and anti seize. The champion rc12yc plugs also supposedly use a coating. Ngk also says its ok to use anti seize upon installation if the plugs have been previously installed and removed. Seems to me the biggest issue is over tightening. I would imagine youd have to tighten a spark plug pretty far to damage it or the head. You should be able to feel the washer crush
