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Holley products deliver the edge you need over the competition. Their Ford modular ignition coil harnesses offer true plug-and-play performance by using OE-style connectors to hook up to your factory coil packs, sensors, or control unit without any modifications. Among other functions, fully connected ECUs allow you to precisely regulate the fuel and ignition of your engine. These Holley complete harnesses enable applications with a single power adder to accommodate a greater number of controls. Order the model designed for your vehicle/engine.
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Choose EFI main power wiring harnesses from Holley to meet your needs. Several choices are offered—TBI, LS applications, multi-point, and un-terminated harnesses—to feed and carry your engine's electrical supply. Get wired for electronic fuel injection with Holley EFI systems main wiring harnesses.
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$549.95
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Holley Dominator EFI vehicle management systems are intended for all engine applications, from street to high-end racing. They have nearly unlimited capabilities to control any power adder, input, or output that you can throw at them. Features include: * 12 sequentially driven 8:2 peak and hold injector drivers capable of driving up to 24 low or high-impedance injectors * 12-channel distributorless ignition outputs capable of directly driving smart ignition coils or Holley DIS coils * Plug-and-play control of factory GM 24x and 58x LSX engines * Integrated electronic transmission control--currently can control GM 4L60E and 4L80E * Integrated dual channel wideband oxygen sensor controls, work with NTK or Bosch sensors * Integrated drive by wire throttle body control, can control two drive by wire throttle bodies * 4-stage progressive nitrous oxide controller * Turbo boost control * Integrated water/methanol injection control * Integrated data acquisition and control allowed with massive amount of programmable inputs and outputs * Internal data logging standard with a huge 2 GB of memory * Self-tuning fuel table strategy greatly simplifies tuning process * Store and change between four calibrations * Individual cylinder fuel and spark control allows you to unlock your engine's potential
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Holley LS coil harnesses are factory replacements for stock LS coils. These EFI LS coil sub harnesses are intended to be used with factory LS coils and various Holley EFI main harnesses with coil-on-plug connectors. They are built with the same high-quality connectors and wire loom found on all Holley EFI harnesses, guaranteeing a perfect match in your engine bay. Are you tired of scouring the junkyard for stock LS coil sub harnesses? Holley has the solution. Holley LS coil harnesses feature: * OEM connectors provide a secure connection between your ECU and Ignition Coils * Techflex F6 braided wire loom keeps your engine bay looking clean, while providing abrasion resistance * Plug-and-play fitment * Can be used to replace a damaged factory coil harness
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Ready for standalone engine management at a budget price? Take control of your GM Gen V LT1, L83, or L86 engine with a Holley Terminator X Max GM Gen V LT direct injection kit! They're available to fit early non-WT drive-by-wire engines, as well as late WT drive-by-wire engines. Terminator X and X Max features and benefits: * Plug-and-play GM Gen V LT engine control, including GDI and VVT support * Ideal for swapping late model GM Gen V LT engines into vintage vehicles * 3.5 in. hand-held gets your engine running in no time with a step-by-step calibration wizard * GM LS and LT drive-by wire throttle body control (Terminator X Max only) * GM 4L60 and 4L80 transmission control (Terminator X Max only) * Included engine harness plugs directly into the factory LT DI injector sub harness * OEM Injectors supported, with part numbers provided in the handheld wizard or software * Genuine Bosch LSU 4.9 wideband control (will not work with LSU 4.2 oxygen sensors) * On-Board Diagnostic LEDS for: ECU Power – Engine Run – Wideband Status – TPS Calibration – Crank Signal – Cam Signal – VVT Status – Pump Control – and DI Injectors. This allows you to identify any critical engine issues at a glance * Built-in 1 bar MAP sensor, vacuum hose adapters included (1/8th, 1/4 and 3/16ths); or for Boosted applications, you can disable the internal MAP sensor, and utilize an external LT MAP sensor. The harness comes with the connector terminated, making the installation a snap * 4 inputs: 12 V, Ground, 5 V, and Frequency—for things such as additional pressure sensors, or activation triggers for nitrous activation, or a trans brake (Fuel and Oil Pressure inputs are pre-terminated) * 4 Outputs: -- Ground -- PWM – for accessories such as fans, boost control, nitrous control, IAC kit, and more -- Boost Control – Boost vs Time, Boost vs Gear, Boost vs RPM, Boost vs Speed, Boost Safeties -- Nitrous Control – Single Channel of Wet or Dry, Progressive or Non-Progressive, Rich/Lean Safeties, and target Closed Loop AFR * Integrated data logging to the 3.5 in. hand-held SD card * Free EFI tuning software for complete control of your Terminator X powerplant Terminator X Max ECU Connections: * J1A - Main Harness Connector: This connector is primarily an "Input" connector. It contains all the sensor inputs and wide band oxygen sensor control. * J1B - Main Harness Connector: The second connector is the "J1B" connector (26 pin). This connector is the "output" connector. It has eight injector outputs and outputs for other devices. * MAP Sensor: Used on N/A applications, connect directly to full manifold vacuum port on the intake manifold. * Main Power: Connects to the Main Power Harness; these two wires MUST be wired directly to the battery terminals. * J3: Connection point for the drive-by-wire harness. * J4: Connection point for the transmission harness.
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$3,049.95
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$3,549.95
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Holley HP EFI smart coil sub harnesses contain two preterminated harnesses designed to work with Holley HP smart coils used on 8-cylinder engines. One end plugs directly into the Holley smart coil, and the other end features a 7-pin Metri-Pak connector that plugs into the Holley universal coil-on-plug harness (HLY-558-307, not included), Holley LSx main harness, or factory GM LSx harnesses.
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Holley EFI Smart Coils are a bolt-in ignition upgrade for your late model HEMI or Coyote engine. Here's the difference over a stock coil: they produce more spark energy while consuming less power without sacrificing voltage output. This means you get hotter spark at the plug to burn the maximum amount of fuel in each cylinder while using less power from your electrical system. Smart Coils are available individually or in sets of 8. * For Coyote or Hemi combinations currently using Holley EFI or Terminator X, use Smart Coil Ignition Harnesses 558-312 and Coil Extension Harnesses 558-326 for a plug-and-play solution. * For new Holley EFI installations on Coyote engines, use with Holley EFI Coyote TI-VCT Main Harness for Smart Coils 558-122 and Smart Coil Ignition Harness 558-312 for a plug-and-play solution. Features: * Direct bolt-on to factory valve covers * Same wiring pinout as other IGN-1A coils for easy plug-in upgrades (Will not work with factory wiring) * More spark energy than any other smart coil on the market for maximum fuel burn during combustion sequence * Low current draw means less demand on the electrical and charging system * Built-in ignitor for compatibility with Holley EFI and many other aftermarket ECUs * Maximum operating voltage of 18 V—for compatibility with both 12 V and 16 V electrical systems found in many performance/race applications
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$799.95
$718.95
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New for the Holley Sniper EFI product line is a factory replacement Sniper EFI canister-style ignition coil. This ignition coil is potted with a premium-grade epoxy, making it perfect for high-vibration environments—and it can be mounted in any direction, even if it's horizontal, vertical, or upside down. "No oil" means "no failure" for multiple mounting positions. The Sniper EFI canister coil is perfect for anyone wanting to upgrade their ignition system, while maintaining a factory look under the hood. Features: * Metal canister is epoxy filled to protect the internal coil windings from high-vibration applications * Improved output coil for electronic ignitions, and MSD ignitions (ballast resistor required for points) * 100:1 turns ratio and lower primary resistance produce high-voltage output
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Designed to extend your factory coil harness so you can easily remote-mount your ignition coils, these wire assemblies by Holley provide an ideal solution for cleaning up the look of your engine bay. They provide the means for mounting your ignition coils off the valve covers with their OEM connectors that provide a secure connection between your ECU and coils. Get the customization you want with the Holley ignition coil extension harnesses designed for your application.
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Holley drive-by-wire throttle body wiring harnesses are designed for use with the Holley Dominator ECU, as well as the factory drive-by-wire throttle body. These harnesses feature pre-terminated connections, ensuring true plug-n-play installation.
Not Yet Reviewed
$474.95
$426.95
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Holley Hemi V8 ignition coil adapter harnesses let you take charge of your engine by controlling both fuel and spark. They are built to fit and function with the factory harness. The harnesses feature TXL-grade copper wiring with minimal weight, plus high-temperature sleeves in a small diameter. Factory-style terminations provide a strong, secure connection.
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2009+ Gen III Hemi engines rolled off the showroom floor with Variable Valve Timing (VVT). Both the Terminator X and Terminator X Max ECUs will allow you to control and tune the VVT with the use of Holley EFI Gen III Hemi VVT harnesses. These plug-and-play harnesses (to the factory sub-harness) provide control of VVT solenoid under the intake manifold.
Not Yet Reviewed
$125.95
Holley Commander 950 wideband replacement O2 sensors are the ultimate additions to any new or existing Commander 950 EFI system. They plug directly into any Commander 950 harnesses and accurately measure any air/fuel ratios between 10:1 and 20:1. This allows the engine tuner to read the air/fuel ratios in real time for extremely precise tuning. These sensors are designed for use with Holley controllers only. They are not intended to be replacement sensors for factory fuel injected vehicles.
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$368.95
On Sale
Holley EFI Smart Coils are a bolt-in ignition upgrade for your Gen III HEMI or Coyote engine. Here's the difference over a stock coil: they produce more spark energy while consuming less power without sacrificing voltage output. This means you get hotter spark at the plug to burn the maximum amount of fuel in each cylinder while using less power from your electrical system. The Smart Coils are available individually and in sets of 8. * For Hemi combinations currently using Holley EFI or Terminator X, use Smart Coil Ignition Harnesses 558-312 and Coil Extension Harnesses 558-326 for a plug-and-play solution. Features: * Direct bolt-on to factory valve covers * Same wiring pinout as other IGN-1A coils for easy plug-in upgrades (Will not work with factory wiring) * More spark energy than any other smart coil on the market for maximum fuel burn during combustion sequence * Low current draw means less demand on the electrical and charging system * Built-in ignitor for compatibility with Holley EFI and many other aftermarket ECUs * Maximum operating voltage of 18 V—for compatibility with both 12 V and 16 V electrical systems found in many performance/race applications
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If you don't feel comfortable cutting up your factory wiring or don't want to attempt to swap pins on your headlight plugs, Holley RetroBright adapters make it a plug-and-play affair. If the standard H4 male plug used on Holley RetroBright headlights will not fit your female socket or you need to swap pins around to match up properly, these harnesses will make the job quick and easy. Additional details: * Allows Holley RetroBright headlights to connect to any non-standard H4 sockets or those that require a pin swap * Eliminates the need to cut factory wiring * Can be used to replace old and brittle factory sockets * Includes two Holley RetroBright H4 adapters
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Holley EFI Gen III Hemi VVT and SRV harnesses offer control. 2009+ Gen III Hemi engines rolled off the showroom floor with Variable Valve Timing (VVT). Now, both Holley Terminator X and Terminator X Max ECUs will allow you to control and tune the VVT with the use of the plug-and-play VVT harness. But the fun does not stop there! If you are using a stock intake manifold that came from the factory with the Short Runner Valve (SRV), Holley also has a plug-and-play sub harness that will allow you to utilize the SRV actuator and capitalize on its low rpm torque benefits. Features: * Plug-and-play with the factory Gen III HEMI VVT sub-harness, and any Holley EFI HEMI main harness connecting to the power tap and input/output connectors * Provides control of VVT solenoid under the intake manifold * SRV (Short runner valve) connector pre-wired into the sub harness allowing you to simply plug into the factory SRV actuator in the intake manifold
Not Yet Reviewed
$163.95
$147.55
Many Toyota vehicles will have a switched ground that doesn't allow Holley's RetroBright headlights to work right out of the box, however Holley has a solution--RetroBright ground switched harnesses. Each harness is designed to switch the ground back, then the headlights can be plugged into the harness, allowing you to enjoy the safety and beauty of RetroBright LED lighting. Installation is easy and effective as there is no special cutting or major reconfiguration of the factory wiring necessary.
Not Yet Reviewed
$27.93
On Sale
Control select Hemi swap project transmissions through Terminator X MAX ECUs with Holley Chrysler transmission wiring harnesses. Terminator X ECUs give you unprecedented control of various components and systems within the drivetrain for enhanced driving performance. And Holley Chrysler transmission wiring harnesses provide plug-and-play compatibility with most factory connectors on select Chrysler transmissions for easier project completion.
Not Yet Reviewed
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$248.35
The factory alternator on the 2020 and up Ford 7.3 L Godzilla engine is a bulky single or dual alternator design that is tough to package in an engine swap. The Holley Ford 7.3L Godzilla alternator kits provide a more compact solution for extra clearance and works with the factory timing cover, water pump, damper/crank pulley, and intake manifold. They also will work with after-market damper/crank pulley. The bracket and alternator are compact and lightweight, and the Holley alternator is easy to wire and does not require the factory ECU to function like the OE alternator. Holley includes the plug/pigtail, pulleys, and belt in a complete kit. Please note the included belt is for alternator-only applications, but the instructions specify the belt for other configurations. The bracket allows for any accessory configuration, and it works with or without the air conditioning compressor and with or without a power steering pump. Features and details: * Alternator kit and mounting bracket for Ford Godzilla 7.3-liter engine swaps * Great solution with everything needed to add an alternator to the Ford 7.3-liter crate engine * Eliminates bulky dual alternator system—factory setup on some heavy-duty trucks * Works with the factory timing cover, water pump, damper/crank pulley, and intake manifold—also works with after-market damper/crank pulley * Compact design with alternator pulled in tight to the engine for extra clearance under the hood * The mounting bracket is compatible with Holley alternator models: PN: 197-300, 197-301, 197-302, and 197-303 * Easy wiring of alternator and does not require factory ECU to excite alternator—wiring pigtail included * Choose from a complete kit with 105-amp Holley alternator (PN: 20-380), or bracket kit (PN: 97-409) * Natural as cast finish on the mounting bracket and alternator * Works with or without an air conditioning compressor * Works with or without a power steering pump * For alternator-only race setup, Holley bracket PN: 97-409 should be used with Holley premium alternator (PN: 197-302 or 197-303)—ideal for high rpm applications (alternator designed and tested for up to 30 percent higher rpm) * Ideal for use on Godzilla crate engines and engine swaps
Not Yet Reviewed
$449.95
On Sale
Holley ECU mounting brackets allow you to comfortably install either the Dominator ECU, Holley HP, Terminator X, or Terminator X-MAX under your Mustang's front passenger seat. They're designed to work with stock seats and seat tracks (modified/race seats may or may not accommodate them). You simply route all your ECU harnesses through the firewall--properly route the wires, install the unit followed by the ECU, and then reconnect your wires and go! Use your laptop to fine-tune the ECU without popping the hood and protect it from engine bay heat with Holley ECU mounting brackets. Order the brackets recommended for your application.
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Holley HP EFI ECU and harness kits allow you to manage automotive functions—like the fuel and ignition of your engine, along with controlling nitrous, boost, or water/methanol. Select the model with options needed for your vehicle application. (Note: some models are engine-specific.) Features and notes: * Eight sequentially driven 8:2 peak and hold injector drivers capable of driving up to 16 low or high-impedance injectors are standard * 8-channel distributorless ignition (DIS) outputs capable of directly driving "smart" ignition coils or Holley DIS coils * Integrated, single-channel wideband oxygen sensor control. Works with NTK or Bosch sensors. More channels can be added via CAN bus. * Internal data-logging is standard, with a huge 2GB of memory * 4-stage progressive nitrous control * Turbo boost control * Integrated water/methanol injection control * Self-tuning fuel table strategy greatly simplifies tuning process * Individual cylinder fuel and spark control allow you to unlock your engine's potential * Compatible with 4, 6, and 8-cylinder engines * Unique lbs./hr.-based fueling strategy greatly simplifies tuning * Advanced idle, closed loop, and enrichment strategies allow for very stable operation * Fully potted and can be mounted in the engine compartment or interior * Sealed automotive and marine-grade connectors * Allows for use of common OEM sensors, as well as customer sensor calibration input * Ignition plug-and-play with GM 24x and 58x LSx engines, GM HEI, Ford TFI, magnetic, and hall effect trigger, and other ignition systems * 1-5 bar MAP sensor capability * 2-channel knock control sensor inputs for both one and 2-wire knock sensors * Dedicated fuel and oil pressure inputs * Control both stepper and PWM idle air control (IAC) motors * Speed density, Alpha-N, or combination fueling strategies * Four programmable high or low pulse width modulated (PWM) outputs and four fully configurable inputs can be configured for use * Lean or rich safety cutoff
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$2,899.95
One of the challenges with a Gen III Hemi swap is alternator clearance. The Holley Gen III Hemi alternator with relocation kit is the solution. These kits come complete with everything you need to move the alternator to a more ideal location to provide additional clearance to the frame on the passenger side of the engine. The kits include the mounting bracket, pulley, alternator and hardware for installation. The alternator is smaller and more compact, further helping clearance issues, making them easy to wire. The steel relocation bracket is black powdercoated for extra rigidity and corrosion-resistance. Make your Gen III Hemi swap easy with one of these Holley kits.
Not Yet Reviewed
$749.95
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