Holley's Big-Wire Coil-Near-Plug Kit gives engine builders precision, individual-cylinder ignition timing control for combinations pushing 5.5+ horsepower per cubic inch, including turbocharged big-block conversions moving to coil-near-plug. The kit bundles two terminated sub-harnesses and eight Holley Smart Coils with pre-wired 12-gauge power and ground connections for reliable high-output spark.
Key Features:
- "Big Wire" sub-harnesses pre-wired with 12-gauge power and grounds
- Two terminated sub-harnesses and eight Holley Smart Coils included
- Sub-harnesses feature fully terminated coil connectors and a 7-pin Metripak connector for use with Holley EFI C-N-P main harnesses
- Includes 3 ft of wiring loom and 3 loose wires for a clean, quick install
- Peak voltage of 44,000V and peak output of 102 mJ
Specifications:
- Peak Voltage: 44,000 Volts
- Peak Output: 102 mJ
- Maximum Battery Voltage: 17.0 Volts
- Coil Terminal Type: HEI-style tower
- Overall Height: 1.86"
- Overall Length: 4.3"
- Overall Width: 3.6"
- Mounting Bolt Pattern: 74mm
- Part Number: 556-128
Upgrading a non coil-near-plug main harness requires Holley's Universal Coil-On-Plug Harness, P/N 558-307, to complete the installation. Connectors and pins are "pull-to-seat" — insert the wire from the back, crimp the pin, and pull it into the connector using proper crimping tools.
Compliance: This part is legal for sale and use on Racing Use Only Vehicles — competition vehicles that are not registered and never operated on the street. It is against the law to install this part on an Emissions Controlled Vehicle (1966-and-newer California-certified or 1968-and-newer federally certified vehicles).
FAQ
What is a coil-near-plug (C-N-P) ignition system?
It's an ignition setup where each coil sits close to its spark plug, shortening the spark path and supporting individual cylinder timing control — useful for high-output and forced-induction builds.
What's included in this kit?
Two terminated Big-Wire sub-harnesses and eight Holley Smart Coils, plus 3 ft of wiring loom and connector hardware for installation.
Do I need an additional harness to run this kit?
Yes, if your main harness isn't already set up for coil-near-plug, you'll need Holley's Universal Coil-On-Plug Harness, P/N 558-307.
Is this kit legal for street use?
No. It's legal for sale and use on Racing Use Only vehicles and cannot be installed on emissions-controlled street vehicles.
