What spark plug?

Seems to me any stock range plug or one that's on the cooler side like rumble suggested would work with that set up. From here on out looks like the thread is going to turn into a "my dad can beat up your dad" kind of thing. But as for autolites, really, I've run 'em in brand x and replaced them within a few hundred miles. I like NGK for European brands as they were OE in most of 'em, especially the new iridiums, but that's a bit over kill with a fairly stock ignition system, not running 30Kv-50Kv through each COP.