NGK LFR6A-11 (3672) Standard Spark Plug - 6 Pack. When your engine requires a dependable spark, the NGK LFR6A-11 (3672) Spark Plug is the answer. This 6-pack is excellent for six-cylinder tune-ups or as a bulk package to have spares on hand for maintenance. With its copper core that transfers heat effectively, every plug helps the engine burn cleanly while minimizing the opportunity for fouling.. The plugs are pre-gapped at 1.1 mm (0.043"), a gap that most popular use. It is still recommended to reference your engine manual before installing. The nickel electrode construction makes these plugs durable against wear, moisture, and corrosion. Under normal automotive use, marine engines, and small equipment, NGK spark plugs give smooth operation and reliable starts day in and day out.. Why Use These Spark Plugs?. 6-pack of plugs - ideal for six-cylinder engines or heavy-duty service needs. Copper core with nickel electrode to ensure consistent combustion. Pre-gapped to 1.1 mm (0.043") to s