last week, my plugs were burning a nice light tan..i was using 8mm Taylor wires. I have now switched to 8.5mm MSD superconductor..both wires were spiro cores. Now, my plugs are burning a clean tan/gray color with a little black sud at the base of the threads. I think i noticed the black suds before, but I figured I am kinda on the lean side, however, the engine doesn't run hot, it actually runs very cool. Both plug readings were check after a few WOT, drives, then idle and shut off. Thanks, Herb
