NGK R5674-8 Extended Tip Racing Spark Plug

The NGK R5674-8 Extended Tip Racing Spark Plug is purpose-built for high-performance and racing applications, engineered to handle extreme combustion temperatures, high cylinder pressures, and demanding engine conditions. Its extended tip design and specialized insulator nose configuration help improve throttle response and ignition efficiency, making it a popular choice for racers and performance enthusiasts seeking reliable spark delivery under load.

Constructed with a pure alumina silicate ceramic insulator, the plug offers exceptional durability, electrical insulation, and enhanced heat transfer. A copper-core center electrode aids in dissipating heat efficiently, while corrugated ribs on the insulator help prevent flashover. Triple sealing technology minimizes the risk of combustion gas leakage, ensuring consistent performance and reliability. The plug features a solid terminal, tapered seat, projected V-cut nickel center electrode, and a factory-set 0.020-inch (0.5mm) gap for optimized ignition performance.

With a 14mm thread diameter, 11mm reach, heat range of 8, and an estimated service life of up to 30,000 miles, the R5674-8 is designed for engines requiring a colder racing plug capable of maintaining stable combustion under aggressive operating conditions.

• Solid Terminal
• 0.5mm Gap
• Sold as Each

Shell

• Thread Diameter - 14mm
• Thread Pitch - 1.25mm
• Seat Type - Tapered
• Reach - 11mm (7/16")
• Hex Size - 5/8" (16mm)
• Terminal Type - Solid
• Overall Height - ISO
• Gap - .020" (0.5mm)

Center Electrode

• Material - Nickel
• Type - V-Cut
• Size - 2.5mm
• Projected  - Yes

Ground Electrode

• Material - Nickel
• Type - Standard
• Quantity - 1

Specifications

• Resistor - No
• Resistor Value - 1K Ohm
• Heat Range - 8
• Torque Specs - Cast Iron: 10.8-18 lb. ft./ Aluminum: 7.2-14.5 lb. ft.
• Longevity - 30k Miles