Just to interject something I know doesn't answer the question. The most detonation resistant plug I've seen with in car, and on dyno experience is an NGK 6061-10. That is against autolite AR series, and champions true race series plugs.

Can't copy the pic, but look at the electrode, and strap arrangement in the link.


http://static.summitracing.com/global/images/prod/large/NGK-5962_w.jpg