Champion 407 Spark Plug

Champion Copper Plus 407 Spark Plug

Champion Copper Plus 407 is a tapered-seat spark plug built for dependable ignition performance in a wide range of Ford, Mercury, Lincoln, and Mazda applications. Its copper core electrode supports strong conductivity and heat control, while the nickel center and ground electrode materials are selected for consistent wear characteristics.

The Copper Plus line focuses on straightforward OE-style service parts for drivers maintaining older ignition systems. For vehicles such as the Ford Mustang, Ford Ranger, and Mercury Cougar, Champion 407 provides a practical replacement option that matches the RS14LC plug type and common factory gap requirements.

Key Features

• Copper core electrode for improved conductivity and heat management
• Nickel center electrode tip and nickel ground electrode core material
• Resistor-type spark plug for secondary ignition systems
• Tapered seat design with a 0.826 reach and 14 mm thread diameter
• Pre-gapped at 0.044 in / 1.11 mm
• Non-removable nut terminal and 5/8 in hex size
• Manufacturer heat range 14
• Champion Copper Plus classification

Product Details

Champion 407 is engineered as a secondary ignition spark plug for vehicles that call for the RS14LC plug type. The copper core helps transfer heat efficiently, while the nickel electrode construction supports stable operation and normal wear over time. This makes it a direct-fit service part for many older Ford, Mercury, Lincoln, and Mazda engines that use tapered-seat plugs.

This part cross-references Autolite 2544 and DENSO Auto Parts 5047 for the same application. Common fitment includes 2000-2004 Ford Focus, 2001-2003 Ford Ranger, 1995-1997 Ford Mustang, 1989-1997 Ford Thunderbird, and 1993-1997 Mercury Cougar.

What It Is Used For

• Replacing worn spark plugs that can cause rough idle
• Restoring consistent spark delivery during acceleration
• Addressing misfire conditions related to plug wear or gap drift
• Maintaining ignition performance in older Ford, Mercury, Lincoln, and Mazda engines
• Servicing vehicles specified for RS14LC tapered-seat spark plugs

Installation Notes and Tips

Verify the vehicle’s required plug type, seat style, and gap before installation. Champion 407 is pre-gapped at 0.044 in, but several listed applications call for a different factory gap, including 0.050 in or 0.054 in. Confirm the engine specification for your Ford Mustang, Ford Ranger, Mercury Cougar, or other listed application before use.

Use proper spark plug service procedures, including checking thread engagement, tightening to the manufacturer’s specification, and inspecting the ignition system for worn wires, coils, or fouled plugs that could affect performance.

Quality Assurance

Champion’s Copper Plus line is built around a copper-core design for conductivity and heat control, with nickel electrode materials chosen for dependable service in everyday ignition applications. The part number 407 is identified as Champion Copper Plus RS14LC and is supported by broad OE-style fitment coverage across 1983-2007 model years.