The NGK 4449 Racing spark plug is a replacement plug. It has M14-1.25 threads, a 0.460 in. reach, a 5/8 in. (16 mm) hex and a heat range of 6. It is built for racing use, with electrode configurations chosen for durability and ignitability under race conditions.

NGK 4449 Racing Spark Plug Features:

• M14-1.25 metric thread with 0.460 in. reach
• 5/8 in. (16 mm) hex
• Tapered seat
• Heat range 6
• 0.032 in. factory pre-gap
• Nickel center electrode tip with nickel ground electrode tip
• Non-resistor design
• Non-removable nut terminal
• 2.070 in. insulator height
• Racing design with special electrode configurations for durability and ignitability under race conditions
• Alumina silicate ceramic insulator for high dielectric strength
• Copper core center electrode draws heat away from the firing end
• Rolled threads help prevent cross-threading in the cylinder head
• Intended for racing use
• Sold individually