Champion Spark Plug C59Y
C Series, 14mm thread, .750" reach
5/8" hex, Projected Tip, Fine Wire Electrode, Warm.
The projected gap style positions the spark an additional 1/8 inch into the chamber and, providing there is sufficient clearance to valves and piston, provides the ultimate in performance. Initiating the flame front closer to the piston top at a given spark has the same effect as advancing the timing. Therefore, maximum timing may be reduced, which helps to reduce detonation and octane requirement and still provides good part throttle response. For normally aspirated engines only; not recommended for turbocharged, supercharged, nitrous oxide or nitro burners.
The fine wire electrode also requires less voltage to jump the gap, which can help compensate for poor fuel mixture or weak ignition at high RPM.