cap'n - this looks almost like those magical "special" electrode shape plugs that are supposed to be better than sliced bread. I'd be real interested in reading any quantitative data/information about what this reworking of electrodes is *known* to have done for an engine's performance.

I've seen things like this done before....the person installs the modified plug, then has to "readjust mixture". Well, the mixture was probably not right in the first place, and the person tweaked the gap through all the screwing around with the plug, and HAD to change things. So they lucked out, adjusted it "better", and decided that the rework of the electrode was the magic cure.

I'm not saying doing what your picture shows doesn't improve something - just wanting actual data to support the benefit of it.

Zman - FWIW, Pe and Pat Roy are the closest to "experts" that I know of on this forum, besides a few others. Your plug looks fine, maybe perhaps just a skosh lean, but what is in the picture doesn't look like a tuning problem.