NGK 6664 Spark Plug

NGK Iridium IX Spark Plug 6664 Overview

NGK Iridium IX Spark Plug 6664 is built for specific Honda and Porsche applications that call for a 14 mm, flat-seat spark plug with a 0.032 in pre-gap. It uses an iridium center electrode tip, copper core center electrode, and a nickel ground electrode core to support consistent ignition performance in the correct heat range.

As part of the NGK Iridium IX Spark Plug line, this plug reflects NGK’s OE-focused manufacturing background and its long history supplying ignition components for domestic and import vehicles. The BR7EIX / 6664 application is a direct match for select classic Honda Accord, Honda Prelude, and Porsche 911 fitments.

Key Features

• NGK Iridium IX Spark Plug, part number 6664
• Iridium center electrode tip material for precise spark delivery
• Copper core center electrode for stable heat transfer
• Nickel ground electrode core with standard ground configuration
• Taper-cut ground electrode tip design
• Pre-gapped to 0.032 in for listed applications
• 14.00 mm thread diameter, 0.75 in reach, flat seat
• 5000 ohm resistance and removable nut terminal
• Heat range 7 with 13/16 hex size

Detailed Description

NGK 6664 is a BR7EIX Iridium IX spark plug engineered for select older performance and street applications where the correct thread size, reach, seat type, and heat range matter. The iridium tip helps maintain a fine firing point, while the copper core and nickel ground electrode support dependable thermal control and ignition consistency. This makes the plug a strong match for owners servicing a 1979 Honda Accord, 1979 Honda Prelude, 1980 Honda Prelude, or classic Porsche 911 applications that specify this exact plug type.

Compatible With: 1980 Honda Prelude, N/A; 1979 Honda Accord, N/A; 1979 Honda Prelude, N/A; 1973 Porsche 911, N/A; 1965-1967 Porsche 911, N/A. This part cross-references AMS Automotive 6664 and Anchor 3095 for the same application.

What This Spark Plug Helps Address

• Hard starting caused by worn or fouled spark plugs
• Misfire conditions from weak or inconsistent spark output
• Rough idle in older Honda and Porsche ignition systems
• Reduced throttle response from degraded plug performance
• Maintenance replacement for the specified BR7EIX application

Installation Notes and Tips

Verify the engine calls for NGK BR7EIX / 6664 before installation. Check the gap and confirm it remains at 0.032 in for the listed fitments, especially on 1979 Honda Accord, 1979 Honda Prelude, 1980 Honda Prelude, and 1965-1967 or 1973 Porsche 911 applications. Use the correct 13/16 in spark plug socket and tighten to the vehicle manufacturer’s specification.

Quality Assurance

NGK is a long-established OE spark plug manufacturer with broad coverage across automotive, motorcycle, marine, and small engine applications. The 6664 Iridium IX spark plug is produced to support original-equipment-level fit and operational performance for the listed vehicles.