I think I'm running too hot a plug right now, seem to be getting some detonation at high RPMs under load, which isn't good. I'm running a set of NGK WR5IX Iridiums, and I think those are too hot. I used to run the NGK WR5's without a problem -- anyone else running a high compression SB with a MSD 6x? I think I may need to go a few steps cooler than the Autolite 45 or WR5, but I don't know what the numbers would be. Ideas?