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. 

Spark Plug Specs:

Gap Size: 0.028
Manufacturer Heat Range: 9
Center Electrode Core Material: Copper Core
Center Electrode Tip Material: Iridium
Ground Electrode Core Material: Nickel Core
Ground Configuration: Standard
Ground Electrode Quantity: 1
Reach: 26.5mm
Resistance: 5K Ohm
Ground Electrode Tip Design: Taper Cut / Trapezoid
Insulator Height: 50.5
Seat Type: Gasket
Center Electrode Tip Material: Iridium
Hex Size: 5/8in
Thread Diameter: 14