Stroker Plugs

Thanks for sharing that, I've been looking for a 5/8 hex equivalent of the Champion Copper Plus RN11YC4 (.040 gap). They are the closest I've seen as of yet, and they're gapped to .043 out of the box, too.
NGK Spark Plugs ZFR6F-11G NGK V-Power Spark Plugs | Summit Racing