Spark Plugs – 48-74 Big Twin

• Plugs have a unique look with their black ceramic body and bold red logo/script
• Insulator is made of 95% pure alumina; features strong resistance to heat shock and superior insulation
• Multi-rib design of insulator eliminates flashover
• Nickel-plated housing prevents oxidation and corrosion
• Multilayer gaskets and heat-crimping process ensure a leak-free, gas-tight fit
• Copper core electrode prevents oxidation and corrosion and has good electrical and heat conductivity for long spark plug service life
• Sold in pairs
• Replacement OEM #: 3-4
• NGK Reference # R5670-5