Fuel Systems - EFI Upgrade Kits

Computer Re-Calibration & Monitoring (ECU) - Non Supercharged Engines

Have you modified your stock Mercury EFI engine by adding high performance exhaust, a bigger cam, a high flow flame arrestor, or added a supercharger?

Hardin Marine can recalibrate your Mercury ECU (computer) to yield the very most of your engines power The ECU precisely controls fuel requirements, detonation control, idle speed and RPM limitations We have dyno-tested multiple combinations and know what works! Call us with your application requirements and we will lead you to maximum horsepower from you EFI engine Allow approximately 4-7 days turn around time.

***Results will vary depending on boat design, propping, atmospheric conditions, environment and drivers. We cannot guarantee speed or plane time increases with the many different applications. MPH and power increase % are helpful rules of thumbs and are in no way guaranteed.

*** We Do not offer any outboard tuning options***

Holley Sniper 2300 EFI Kit - Shiny or Black Ceramic

Using the Sniper EFI 2300 you can put an end to cold start issues, hesitations, vapor lock, and flooding on your Fairlanes, Galaxies, Falcons, Comets, F100s, Javelins, Rebels, Mustangs, Thunderbirds, Cougars and more. A Sniper kit is the #1 way to upgrade your classic to fuel injection in a cost-efficient way with just 4 simple connections required. After a simple installation designed to be completed at home in your garage or driveway with limited tools and the support of Holley's comprehensive installation manual and videos, you'll be enjoying better engine performance, improved miles per gallon and easier starting. This kit supports up to 350 Horsepower Naturally Aspirated and 285 Horsepower on Forced Induction setups with 2 x 100 Lb/Hr Injectors.

You don't have to be a tuning genius or computer wiz to convert your build to EFI. Our simple calibration wizard allows you to just answer a few questions about your engine and the system will begin self-tuning with no laptop required. Use the high resolution 3.5" full color touchscreen for tuning and gauge displays.

Now that you're beginning your EFI journey, you don't have to stop here! Sniper is apart of a complete ecosystem designed specifically to work together and support all of your EFI needs. This kit pair's seamlessly together with plug-n-play Hyperspark Ignition systems (coil, ignition box and distributors), fuel system's (fuel pump kits, modules, in-tank systems), air cleaners & digital dashes to unlock the full potential of your build.

• Bolt on 2300 Flange Carburetor Replacement
• Self-tuning ECU means you don't have to be a computer/tuning wiz to have EFI!
• Simple Calibration Wizard (answer a few questions about your engine and it creates the base map, then starts tuning on its own!) - NO laptop required!
• Only 4 Wiring Connections Required! (Battery +, Battery - , Switched Ignition & RPM)
• High Resolution Full Color Touchscreen for Initial Setup, Tuning, and Gauge Displays
• Supports up to 350HP with Two 100lb/hr Injectors
• Equipped with C4 / C6 Ford transmission kickdown lever as well as TH350, 400 and 700R4 provisions
• Accepts many common 5 1/8" OEM or aftermarket air cleaner assemblies
• Throttle body mounted ECU – no extra boxes to mount
• Integrated ignition timing control
• Internal fuel pressure regulator eliminates the hassle of plumbing an external fuel pressure regulator (Preset to 58.5 PSI)
• The included Genuine Bosch LSU 4.9 Wideband Oxygen Sensor provides realtime Fuel Map Learn!
• OEM Style TPS/IAC and Fuel Pressure regulator, for years of dependable service.
• Included clamp-on oxygen sensor kit for 2.25" exhaust ensures a leak free oxygen sensor installation, with Stainless Steel T-Bolt clamps and a Stainless Steel (Weldable) oxygen sensor flange
• Sniper EFI Software free to download which allows for realtime tuning
• Printable throttle body flange template included
• Certified to ISO 8846, SAE J1171 & United States Coast Guard Requirements for Ignition Protection & Fire Resistance. Making Sniper EFI the perfect choice for carburetor to marine fuel injection conversions!
• A Flame Arrestor is REQUIRED for marine installations, such as part number, 720-1 or 720-13

Holley Super Sniper Quadrajet EFI Kit - Shiny, Black Ceramic or Classic Gold

Are you tired of rebuilding the 50+ year old Rochester™ Quadrajet® (Q-Jet™) on your classic Chevrolet, GMC, Buick, Oldsmobile, or Pontiac? The Sniper EFI Quadrajet™ is here to help! The first bolt-on spreadbore electronic fuel injected throttle body system that does not require any additional adapters, sealing plates, or intake manifold swaps! The Sniper EFI Rochester Quadrajet™ (Q-Jet) system retains the same great features as the 4150 Sniper EFI version such as; four 100lb/hr Injectors, built-in timing control, a 3.5" full-color touchscreen, and much more! This throttle body will support up to 500 horsepower naturally aspirated. In addition to all of these great tried and true features, the Sniper EFI Rochester Quadrajet™ (Q-Jet) system will fit most stock air cleaners and offers multiple fuel inlet configurations that allow for a stock appearing installation!

When it comes to converting to EFI, Sniper is the absolute best way to upgrade your car to fuel injection with just 4 simple connections required. Sniper is designed to be installed at home in your garage or driveway with limited tools and the support of Holley's comprehensive installation manual and videos. An afternoon in the garage and you will be enjoying improved engine performance, better MPG's and easier starting. After the simple installation it's time to let your Sniper begin the self-tuning process. Our user-friendly calibration wizard allows you to just answer a few questions about your engine and the system will begin self-tuning with no laptop required. You don't have to be a computer wiz or specialize in tuning to use a Sniper EFI system! Use the high resolution 3.5" full color touchscreen for tuning and gauge displays.

Sniper EFI is part of a complete ecosystem! Your new Sniper kit pair's seamlessly together with Holley's Sniper Hyperspark Ignition, Fuel System's, Air Cleaners, Throttle Body & Digital Dash to unlock the full potential of your build. Complete your fuel injection journey by checking out our full offer of ignition, fueling and accessories!

• Fits most stock Rochester Quadrajet™ (Q-Jet) air cleaners
• Self-tuning ECU means you don't have to be a computer/tuning wiz to have EFI!
• Simple Calibration Wizard (Answer a few questions about your engine and it creates the base map, then starts tuning on its own!) - NO laptop required!
• Only 4 Wiring Connections Required! (Battery +, Battery - , Switched Ignition & RPM)
• High Resolution Full Color Touchscreen for Initial Setup, Tuning, and Gauge Displays.
• Supports up to 500hp with Four 100 Lb/Hr Injectors!
• Throttle body mounted ECU – no extra boxes to mount
• Designed to deliver the signature Rochester Roar at Wide Open Throttle!
• Integrated ignition timing control
• Transmission provisions on throttle lever for TH350/TH400 and 200R4/700R4
• Brake Booster adapter included, if required
• Universal Throttle and transmission kickdown bracket included
• The included Genuine Bosch LSU 4.9 Wideband Oxygen Sensor provides realtime Fuel Map Learn!
• OEM Style Throttle Position Senser (TPS)/ and Idle Air Control (IAC) for years of dependable service.
• Included clamp-on oxygen sensor kit ensures a leak free oxygen sensor installation, with Stainless Steel T-Bolt clamps and a Stainless Steel (Weldable) oxygen sensor flange
• Certified to ISO 8846, SAE J1171 & United States Coast Guard Requirements for Ignition Protection & Fire Resistance. Making Sniper EFI the perfect choice for carburetor to marine fuel injection conversions!
• A Flame Arrestor is REQUIRED for marine installations, such as part number, 720-1 or 720-13
• Requires external fuel pressure regulator, such as: 12-886 or 12-879

Holley Super Sniper Stealth 4500 EFI Self-Tuning Kit - Shiny, Black Ceramic or Classic Gold

Wanting to convert your Dragster or Pro-street vehicle to Fuel Injection? Sniper, the #1 Fuel Injection Conversion system has you covered with the Stealth 4500. Featuring 8 100LB/HR Fuel Injectors this kit is the perfect option for any build looking to make between 800-1500HP. We have many Sniper options for builds going from mild to wild. This is the perfect set up for the more extreme build with multiple input and output options for sensor inputs and switched outputs to control external relays. 2.125" throttle plates, flows 1440 CFM for larger cubic inch engines. Included 2.5BAR Map sensor and programmable launch control via 2-step which can be triggered by the trans-brake input.

Simplicity is what we strive for when it comes to everything related to EFI conversion! Sniper is designed to be installed at home in your garage or driveway with limited tools and the support of Holley's comprehensive installation manual and videos. An afternoon in the garage and you will be enjoying improved engine performance, better MPG's and easier starting. You don't have to be a computer wiz or tuning professional to run a sniper kit on your build. Our calibration wizard allows you to just answer a few questions about your engine and the system will begin self-tuning with no laptop required. Use the high resolution 3.5" full color touchscreen for tuning and gauge displays.

Once you made your conversion to EFI, don't stop there! Sniper is an Ecosystem! This kit pair's seamlessly together with Holley's Sniper Hyperspark Ignition, Fuel System's, Air Cleaners, Throttle Body & Digital Dash to unlock the full potential of your build.

For a full list of features & benefits on what the Sniper Stealth 4500 has to offer, see below!

• Supports up to 1500HP Naturally Aspirated & 1250HP Boosted!
• Self-tuning ECU means you don’t have to be a computer/tuning wiz to have EFI!
• Simple Calibration Wizard (Answer a few questions about your engine and it creates the base map, then starts tuning on its own!) - NO laptop required
• Only 4 Wiring Connections Required! (Battery +, Battery - , Switched Ignition & RPM)
• Compatible with Draw through or Blow through forced induction applications
• High Resolution Full Color Touchscreen for Initial Setup, Tuning, and Gauge Displays
• 2.125” Throttle Plates, Flow 1440 CFM for large cubic inch engines
• 2.5Bar MAP Sensor
• Integrated ignition timing control
• Programmable launch control via 2-step and timing retard. Both can be triggered by a trans-brake input
• Gen 3 Ultra Dominator Style 4 Bolt Air Cleaner Flange
• -8AN Fuel Inlets
• The included Genuine Bosch LSU 4.9 Wideband Oxygen Sensor provides realtime Fuel Map Learn
• Built-in Single Stage Wet or Dry progressive nitrous control
• Three Programmable 0-5V Sensor Inputs for Oil/Fuel/Dome or Nitrous Pressure or other critical information
• Six Programmable Ground Outputs, Five programmable ground inputs. These can be used to trigger or control external devices such as nitrous solenoids, boost control solenoids. Or to provide the ECU with an Input to turn on function such as an ignition timi
• One +5v Reference Output - +5V Power Supply for 0-5v Sensors, One Sensor Ground – Ground supply for 0-5v Sensors
• Throttle body mounted ECU – no extra boxes to mount
• Required external fuel pressure regulator, 12-848 is recommended
• Customizable secondary fuel pump output (TPS, RPM or Boost enabled)
• User friendly Boost Control with handheld adjustability
• Free Software included comprehensive datalogging tool to help you maximize the performance of your engine
• Real-time datalogging to the included 3.5” Touch Screen, allows you to save information to the SD card without needing a communication cable
• Programmable Target Air Fuel Ratios per Boost level
• Advanced boost control available via free Sniper EFI tuning software, including Boost vs RPM and Boost vs Time
• OEM Style TPS/IAC, for years of dependable service
• Included clamp-on oxygen sensor kit ensures a leak free oxygen sensor installation, with Stainless Steel T-Bolt clamps and a Stainless Steel (Weldable) oxygen sensor flange
• Patent Pending

Holley Super Sniper 2300 EFI Kit - Shiny, Black Ceramic or Classic Gold

Looking to convert your blow thru carbureted turbo engine to EFI? Look no further! Using the Sniper EFI 2300 you can put an end to cold start issues, hesitations, vapor lock, and flooding on your Fairlanes, Galaxies, Falcons, Comets, F100s, Javelins, Rebels, Mustangs, Thunderbirds, Cougars and more. A Sniper kit is the #1 way to upgrade your classic to fuel injection in a cost-efficient way with just 4 simple connections required. After a simple installation designed to be completed at home in your garage or driveway with limited tools and the support of Holley's comprehensive installation manual and videos, you'll be enjoying better engine performance, improved miles per gallon and easier starting. This kit supports up to 350 Horsepower Naturally Aspirated and 650 Horsepower on Forced Induction setups with 4 x 100 Lb/Hr Injectors.

Did we mention the Super Sniper also has full nitrous control built-in? That's right, no need for a separate nitrous controller! Every Super Sniper EFI system also comes with a USB to CAN tuning cable, as well as free downloadable Sniper EFI Software to give you unlimited control of your engine. Bolt-on replacement for popular classic Holley carburetors such as the 0-4412 or 0-7448.

You don't have to be a tuning genius or computer wiz to convert your build to EFI. Our simple calibration wizard allows you to just answer a few questions about your engine and the system will begin self-tuning with no laptop required. Use the high resolution 3.5" full color touchscreen for tuning and gauge displays.

Now that you're beginning your EFI journey, you don't have to stop here! Sniper is apart of a complete ecosystem designed specifically to work together and support all of your EFI needs. This kit pair's seamlessly together with plug-n-play Hyperspark Ignition systems (coil, ignition box and distributors), fuel system's (fuel pump kits, modules, in-tank systems), air cleaners & digital dashes to unlock the full potential of your build.

• Bolt on 2300 Flange Carburetor Replacement
• Self-tuning ECU means you don't have to be a computer/tuning wiz to have EFI!
• Simple Calibration Wizard (answer a few questions about your engine and it creates the base map, then starts tuning on its own!) - NO laptop required!
• Only 4 Wiring Connections Required! (Battery +, Battery - , Switched Ignition & RPM)
• High Resolution Full Color Touchscreen for Initial Setup, Tuning, and Gauge Displays
• Throttle body mounted ECU – no extra boxes to mount
• Supports forced induction up to 650HP with four 100lb./hr. Injectors
• Dry or wet nitrous support
• 2.5 Bar MAP sensor included which safely works on applications up to 21.5 PSI
• Internal fuel pressure regulator eliminates the hassle of plumbing an external fuel pressure regulator (Preset to 58.5 PSI)
• Compatible with draw-thru or blow-thru forced induction applications
• User-friendly boost control with handheld adjustability
• Programmable target air fuel ratios per boost level
• Advanced boost control is available via free Sniper EFI tuning software, including Boost vs RPM and Boost vs Time.
• Built-in single stage progressive or non-progressive nitrous control strategies
• The included Genuine Bosch LSU 4.9 Wideband Oxygen Sensor provides realtime Fuel Map Learn!
• OEM Style TPS/IAC and Fuel Pressure regulator, for years of dependable service.
• Included clamp-on oxygen sensor kit for 2.25" exhaust ensures a leak free oxygen sensor installation, with Stainless Steel T-Bolt clamps and a Stainless Steel (Weldable) oxygen sensor flange
• Equipped with C4 / C6 Ford transmission kickdown lever as well as TH350, 400 and 700R4 provisions
• Accepts many common 5 1/8" OEM or aftermarket air cleaner assemblies
• Printable throttle body flange template included
• Certified to ISO 8846, SAE J1171 & United States Coast Guard Requirements for Ignition Protection & Fire Resistance. Making Sniper EFI the perfect choice for carburetor to marine fuel injection conversions!
• A Flame Arrestor is REQUIRED for marine installations, such as part number, 720-1 or 720-13

Computer Re-Calibration & Monitoring (ECU) - Supercharged Engines

Have you modified your stock Mercury EFI engine by adding high performance exhaust, a bigger cam, a high flow flame arrestor, or added a supercharger?

Hardin Marine can recalibrate your Mercury ECU (computer) to yield the very most of your engines power The ECU precisely controls fuel requirements, detonation control, idle speed and RPM limitations We have dyno-tested multiple combinations and know what works! Call us with your application requirements and we will lead you to maximum horsepower from you EFI engine Allow approximately 4-7 days turn around time.

***Results will vary depending on boat design, propping, atmospheric conditions, environment and drivers. We cannot guarantee speed or plane time increases with the many different applications. MPH and power increase % are helpful rules of thumbs and are in no way guaranteed.

ECM 555 Computer Re-Calibration & Monitoring (ECU) - 496 Mag and HO, 525 Non Supercharged Engines

Have you modified your stock Mercury EFI engine by adding high performance exhaust, a bigger cam, a high flow flame arrestor, oradded a supercharger?

Hardin Marine can recalibrate your Mercury ECU (computer) to yield the very most of your engines power The ECU precisely controls fuel requirements, detonation control, idle speed and RPM limitations We have dyno-tested multiple combinations and know what works! Call us with your application requirements and we will lead you to maximum horsepower from you EFI engine. Allow approximately 4-7 days turn around time.

***Results will vary depending on boat design, propping, atmospheric conditions, environment and drivers. We cannot guarantee speed or plane time increases with the many different applications. MPH and power increase % are helpful rules of thumbs and are in no way guaranteed.

"SE" Special Edition Tuning Kit For MerCruiser 454 & 502 Magnum MPI Engines

This kit is an excellent choice for those just beginning performance modifications on a MerCruiser Magnum EFI Series engine. This kit includes the "SE" Special Edition flame arrestor that utilizes a high flow K&N clamp-on style filter element and high velocity air inlet adapter which increases air flow by as much as 20%. The included Flow Command adjustable fuel pressure regulator allows you to tune to the proper air flow by allowing adjustments from 25 to 65 PSI.

"SS" Sport Series Tuning Kit For MerCruiser 454 & 502 Magnum MPI Engines

Do you want quicker acceleration, faster planing, and increased performance of up to 15 HP? If so, the "SS" Super Sport tuning kit for your MerCruiser Magnum MPI engine is what you need. This kit includes the "SS" Sport Series flame arrestor that utilizes a clamp-on style K&N element with our high velocity style air inlet. This kit include re-programming of your factory ECU in which we will modify both the fuel and spark curves as well as increasing your rev limiter and injector timing to 5400 RPM. This kit also comes with an adjustable billet Flow Command fuel pressure regulator that allows you to tune your air fuel mixture for optimum performance.

NOTE: You will need to send us your ECU with this questionnaire for re-calibration.

***Results will vary depending on boat design, propping, atmospheric conditions, environment and drivers. We cannot guarantee speed or plane time increases with the many different applications. MPH and power increase % are helpful rules of thumbs and are in no way guaranteed.

Holley Super Sniper 1250 EFI Self-Tuning Kit - Shiny, Black Ceramic or Classic Gold

Introducing Holley Super Sniper EFI! Looking to convert your blow thru carbureted turbo engine to EFI?Look no further than Holley for the Super Sniper 4150 EFI systems featuring 8, 100LB/HR Fuel Injectors capable of supporting up to 1250 HP on forced induction or dry nitrous applications. Is your combination not producing that much horsepower? No problem, Holley also offers a 650 HP four injector version for lower horsepower applications with a power adder or someone just needing additional sensor inputs. Did we mention the Super Sniper also has full nitrous control built-in? That's right, no need for a separate nitrous controller! Every Super Sniper EFI system also comes with a USB to CAN tuning cable, as well as free downloadable Sniper EFI Software to give you unlimited control of your engine.

• 1250 HP version features eight 100 Lb/Hr Injectors (Forced Induction)
• The 800 CFM Main Body will support 700 Horsepower Naturally Aspirated
• Compatible with Draw thru or blow thru forced induction applications
• Built-in Single stage progressive nitrous control
• Programmable inputs and outputs
• Integrated ignition timing control for precise timing curves
• Only 4 Wiring Connections Required! (Battery +, Battery-, Switched Ignition & RPM)
• Internal fuel pressure regulator eliminates the hassle of plumbing an external fuel pressure regulator (Preset to 58.5 PSI) for N/A or Nitrous applications
• Self-tuning ECU means you don't have to be a computer/tuning wiz to have EFI!
• High-Resolution Full Color Touchscreen for initial Setup, Tuning, and Gauge Displays
• Simple Calibration Wizard (Answer a few questions about your engine, and it creates the base map, then starts tuning on its own!) - NO laptop required!
• The included Genuine Bosch LSU 4.9 Wideband Oxygen Sensor provides real-time Fuel Map Learn!
• OEM Style TPS/IAC and fuel pressure regulator, for years of dependable service
• Included clamp-on oxygen sensor kit ensures a leak-free oxygen sensor installation, with Stainless Steel T-Bolt clamps and a Stainless Steel (Weldable) oxygen sensor flange
• Throttle body mounted ECU – no extra boxes to mount
• USB to CAN Communication cable included for easy laptop tuning of advanced controls
• Dual Pattern bolt on carburetor replacement, designed to fit 4150 Flange & Spread Bore manifolds - (Spread Bore Sealing Plate Part #9006 recommended)
• Certified to ISO 8846, SAE J1171 & United States Coast Guard Requirements for Ignition Protection & Fire Resistance. Making Sniper EFI the perfect choice for carburetor to marine fuel injection conversions!
• A Flame Arrestor is REQUIRED for marine installations, such as part number, 720-1 or 720-13
• Compatible with Holley EFI analog gauges and electronic dashes
• Patent Pending

Holley Super Sniper 650 EFI Self-Tuning Kit - Shiny, Black Ceramic or Classic Gold

Introducing Holley Super Sniper EFI! Looking to convert your blow thru carbureted turbo engine to EFI? Look no further. Holley offers a 650 HP four injector version for lower horsepower applications with a power adder or someone just needing additional sensor inputs. Did we mention the Super Sniper also has full nitrous control built-in? That's right, no need for a separate nitrous controller! Every Super Sniper EFI system also comes with a USB to CAN tuning cable, as well as free downloadable Sniper EFI Software to give you unlimited control of your engine.

• 650 HP version features four 100 Lb/Hr Injectors
• Compatible with Draw-Thru or Blow-Thru forced induction applications
• User-friendly Boost Control with handheld adjustability
• Programmable Target Air Fuel Ratios per Boost level
• Advanced boost control is available via free Sniper EFI tuning software, including Boost vs RPM and Boost vs Time – Same popular boost control offered in Holley HP and Dominator EFI systems!
• 2.5 Bar MAP sensor included which safely works on applications up to 21.5 PSI
• Built-in Single stage progressive nitrous control
• Dry or Wet Nitrous Support
• Progressive or Non-Progressive control strategies
• Lean/Rich AFR Cutoff
• Time or RPM based Timing Retard and much more!
• Integrated ignition timing control for precise timing curves
• Programmable inputs and outputs
• Three Programmable 0-5V Sensor Inputs for Oil/Fuel/Dome or Nitrous Pressure Sensors
• Six Programmable Ground Outputs
• One +5v Reference Output - +5V Power Supply for 0-5v Sensors
• One Sensor Ground – Ground supply for 0-5v Sensors
• Internal fuel pressure regulator eliminates the hassle of plumbing an external fuel pressure regulator (Preset to 58.5 PSI) for N/A or Nitrous applications
• Self-tuning ECU means you don't have to be a computer/tuning wiz to have EFI!
• Only 4 Wiring Connections Required! (Battery +, Battery-, Switched Ignition & RPM)
• High-Resolution Full Color Touchscreen for initial Setup, Tuning, and Gauge Displays
• Simple Calibration Wizard (Answer a few questions about your engine, and it creates the base map, then starts tuning on its own!) - NO laptop required!
• The included Genuine Bosch LSU 4.9 Wideband Oxygen Sensor provides real-time Fuel Map Learn!
• OEM Style TPS/IAC and fuel pressure regulator, for years of dependable service
• Included clamp-on oxygen sensor kit ensures a leak-free oxygen sensor installation, with Stainless Steel T-Bolt clamps and a Stainless Steel (Weldable) oxygen sensor flange
• Throttle body mounted ECU – no extra boxes to mount
• USB to CAN Communication cable included for easy laptop tuning of advanced controls
• Dual Pattern bolt on carburetor replacement, designed to fit 4150 Flange & Spread Bore manifolds - (Spread Bore Sealing Plate Part #9006 recommended)
• Certified to ISO 8846, SAE J1171 & United States Coast Guard Requirements for Ignition Protection & Fire Resistance. Making Sniper EFI the perfect choice for carburetor to marine fuel injection conversions!
• A Flame Arrestor is REQUIRED for marine installations, such as part number, 720-1 or 720-13
• Compatible with Holley EFI analog gauges and electronic dashes
• Patent Pending

Mercury Racing 700 Intercooler Hi-Flow Fitting Kit

This fitting kit replaces the stock fittings with larger higher flow fittings allowing better cooling performance. Fittings are -10 AN.