Compare Maximum number of 4 items selected Champion Racing Spark Plug - 657 Part #: 657 Line: CHP Champion Racing Spark Plug Manufacturer's Defect Warranty Seat: Flat Thread Size: M10 Heat Range: 55 Hex Size (mm): 16mm Hex Size (in): 5/8 Inch Preset Gap (in): 0.018 To 0.023 Inch Preset Gap (mm): 0.46mm To 0.58mm Thread Reach (in): 0.750 Inch Resistor Plug: No Center Electrode Tip Material: Nickel-Copper Alloy Insulator Height (in): 1.990 Inch Ground Electrode Tip Material: Nickel Show More Show Less