NGK 6578 Spark Plug

NGK 6578 Standard Spark Plug Overview

NGK 6578 is a standard spark plug built for OE-style ignition performance across a wide range of domestic and import applications. With a copper center electrode core, nickel tip materials, and a 5,000 ohm resistor, it supports stable spark delivery for everyday driving and routine tune-up service.

As part of NGK’s Standard Spark Plug line, this plug reflects the brand’s long OE supply background and focus on original-equipment specifications. It is a direct replacement choice for many Chrysler, Dodge, Jeep, Plymouth, and other classic vehicle applications that call for a flat seat, 14 mm thread, and 0.75 inch reach.

Key Features

• Part number 6578, NGK BPR4ES SOLID
• Standard spark plug design with OE-style construction
• Copper center electrode core for dependable conductivity
• Nickel center and ground electrode tip materials
• 5,000 ohm resistor for ignition system noise suppression
• Pre-gapped at 0.032 inch
• Flat seat, 14 mm thread diameter, 0.75 inch reach
• Single ground electrode with standard configuration
• 13/16 inch hex size for common service tools

Detailed Description

NGK 6578 is engineered for drivers and restorers who need a standard replacement spark plug that matches OE-style dimensions and service expectations. The plug’s copper core helps promote consistent heat transfer, while the nickel electrode design supports reliable ignition in a broad range of older vehicles. This makes it a practical choice for maintenance on Dodge Caravan, Dodge Dakota, Jeep Grand Wagoneer, Plymouth Voyager, and many other applications listed in the fitment data.

This part cross-references Autolite 405 and Hella 67 for the same application. The NGK 6578 spark plug is also identified as BPR4ES SOLID, which helps when matching service parts by alternate numbering.

What It Helps Address

• Hard starting caused by worn or fouled spark plugs
• Rough idle from inconsistent spark delivery
• Misfire symptoms tied to aged ignition components
• Reduced throttle response from degraded plug performance
• Routine tune-up needs on older Chrysler, Dodge, Jeep, and Plymouth vehicles

Installation Notes and Tips

Verify the required plug gap and thread reach before installation. This plug is pre-gapped at 0.032 inch, while many listed applications reference OE service gaps around 0.035 inch or similar; confirm the specification for your exact engine before use. Use the correct 13/16 inch spark plug socket, tighten to the vehicle manufacturer’s torque specification, and inspect plug wires or coil components during service.

Compatible With many 1955-1995 Chrysler, Dodge, Jeep, Plymouth, Mercury, Pontiac, Chevrolet, Cadillac, Oldsmobile, Rolls-Royce, Bentley, and GMC applications listed in the fitment data, including Fits 1988-1995 Dodge Caravan, N/A; Fits 1987-1995 Dodge Dakota, N/A; Fits 1984-1987 Jeep Grand Wagoneer, N/A; and Fits 1967-1969 Chevrolet Camaro, N/A.

Quality Assurance

NGK is a major OE spark plug supplier in North America with more than 80 years of automotive manufacturing experience. Its Standard Spark Plug line is built to original-equipment standards for durability and consistent operation across a wide range of vehicle applications.