Champion Spark Plug G55R
G Series, 10mm thread, .750" reach
5/8" hex, Retracted Gap, Extremely Cold.
The Retracted gap style moves the spark approximately 1/16 inch outside the combustion chamber. This style is sometimes required when the piston or valves do not allow clearance with a standard plug design. The retracted gap is most commonly used with supercharged or nitro-burning drag racing engines, where cylinder temperatures and pressures are extremely high. It is NOT appropriate for any street-driven applications!