MSD 3406 Blue 8mm Heli-Core Universal Single Replacement Spark Plug Wire

The MSD 3406 is a single universal replacement spark plug wire built with MSD's proven Heli-Core 8mm construction in a distinctive blue jacket. Designed for racers and performance enthusiasts who need a reliable, low-resistance wire that delivers maximum ignition energy to the spark plug while suppressing electromagnetic interference.

Key Features:

• 8mm Heli-Core Design: The copper alloy conductor is wound tightly around a special center core — over 40 feet of conductor is wrapped into a single foot of wire — delivering exceptionally low resistance of just 40–50 ohms per 12 inches
• EMI Suppression: The helical winding combined with a ferro-magnetic impregnated center core creates a highly effective EMI choke, keeping electromagnetic interference contained and away from sensitive vehicle electronics
• 48-Inch Wire Length: Supplied as a single 48" wire, allowing you to trim it to your exact required length for a clean, custom fit
• Dual-Angle Terminals Included: Comes with a multi-angle terminal and boot on one end, a 90-degree HEI-style terminal on the other, plus an additional 90-degree socket terminal and boot — providing flexible routing options
• Mini Stripper/Crimper Included: A compact stripper/crimper tool is included so you can tailor the wire to your needed length and install terminals with a secure connection
• Dual Crimp Terminal Design: MSD's Dual Crimp terminals feature two separate crimps — one securing the wire sleeve and another independently gripping the conductor — for a more secure connection with reduced risk of arcing
• High-Heat Resistant Outer Sleeve: The outer jacket is made from a proprietary blend of silicone and synthetic materials, providing excellent resistance to high temperatures, abrasion, and tearing
• Blue Jacket: Bold blue color for easy identification in the engine bay

The MSD 3406 universal single replacement wire is ideal for custom ignition builds, header clearance applications, or replacing a single damaged wire in an existing set. The included terminals and crimper make it easy to cut and configure the wire for virtually any engine layout.