These are the standard Zuma Plugs. The 7 is the hottest and  the 8 is the coldest.

The 7 is standard from the factory. Most folks run an 8. It is important that you use a short reach extended tip resistor plug!

Call us with any questions: 831-484-1921 M-F 9am-5pm Pacific (Noon-8pm Eastern)

NGK's Standard Plugs are Constructed for Longer Life and Optimum Performance.
    Trivalent Metal Plating Provides Superior Anti-Corrosion and Anti-Seizing Properties
    Corrugated Ribs Prevent Flashover
    Pure Alumina Silicate Ceramic Insulator, Provides Superior Strength and Better Heat Transfer
    Copper Core Aids in Heat Removal
    Triple Seals Prevent Leakage

Spark Plug Cap and Boot available and a great spark checker