NGK 7401 Spark Plug

NGK Iridium IX Spark Plug 7401

NGK Iridium IX Spark Plug 7401 is built for drivers who want precise ignition performance and OE-style reliability. With an iridium center electrode, copper core, and tapered seat design, this spark plug supports consistent combustion across a wide range of classic Ford, Chevrolet, GMC, Dodge, Pontiac, Buick, and Cadillac applications.

Part number 7401 is also referenced as UR4IX, making it easier to match the correct plug when servicing older V8 and inline applications. This NGK Iridium IX spark plug is a direct service choice for vehicles such as the Ford F-150, Chevrolet Camaro, and GMC Jimmy where the listed gap and heat range matter.

Key Features

• Iridium center electrode tip for stable spark delivery
• Copper core center electrode for efficient heat transfer
• Taper cut ground electrode tip design
• Standard ground configuration with one ground electrode
• 5,000 ohm resistance
• Tapered seat design with 14 mm thread diameter
• Pre-gapped at .040 inch; verify against vehicle-specific gap requirements
• NGK part number 7401 / UR4IX

Product Details

NGK’s Iridium IX Spark Plug line is backed by the company’s long OE supply history and broad coverage across domestic and import vehicles. The 7401 plug uses an iridium tip for the center electrode, a nickel ground electrode core, and a copper core center electrode to support dependable ignition performance in demanding secondary ignition systems. Its 5/8 hex, .46 reach, and tapered seat configuration make it a strong service match for many older applications that specify a 14 mm spark plug.

Compatible With applications including Fits 1975-1996 Ford E-350 Econoline, Fits 1973-1996 Ford F-250, Fits 1973-1996 Ford F-350, Fits 1987-1992 Chevrolet Camaro, and Fits 1979-1984 GMC C1500. Additional coverage includes many Chevrolet Caprice, Pontiac Firebird, Dodge D-series, and Buick Regal applications listed in the fitment data.

This part cross-references Bosch 7401 for the same application.

Common Issues This Plug Can Address

• Weak or inconsistent spark from worn conventional plugs
• Hard starting caused by degraded ignition performance
• Rough idle in older carbureted or fuel-injected engines
• Misfire complaints tied to incorrect plug wear or gap condition
• Service intervals that require a fresh ignition tune-up component

Installation Notes and Tips

• Verify the vehicle-specific gap before installation; listed applications call for gaps such as 0.035, 0.040, 0.044, or 0.045 inch depending on engine and year.
• Confirm the tapered seat and 14 mm thread size match the cylinder head specification.
• Use the correct torque procedure for the engine to avoid thread or seat damage.
• Check plug wire or coil condition during service to protect ignition performance.
• Review the exact year, make, model, and engine notes in the fitment list before ordering.

Quality Assurance

NGK is a major OE spark plug supplier with more than 80 years of automotive manufacturing experience. The brand’s North American and global production and distribution network supports consistent product availability and OE-level manufacturing standards for ignition service parts.