NGK 4654 Iridium Racing Spark Plug (4 Pack)

NGK Racking Plugs are designed for use in engines that have been tuned to achieve maximum power under specific racing conditions.

These spark plugs are two stages colder vs the OEM plugs

What does Heat Range mean?

"Generally, low power engines such as lawn mowers don’t produce a large amount of heat, hence use a low heat range (or hot) spark plug such as a 4 heat range. This means the spark plug will heat up easily and reach its optimal operating temperature. High performance engines on the other hand produce a large amount of heat, hence a high heat range (or cold) spark plug such as a 10 heat range needs to be used to resist the heat developed by the engine." - NGK

These plugs will work best on cars that are stage 2+ or higher.