Holley Sniper EFI

Holley Sniper EFI Self-Tuning Master Kit - Black Ceramic Finish

Holley Sniper 4 Barrel Fuel Injection Conversion - Self-Tuning Master Kit + Handheld EFI Monitor - Black Ceramic Finish

Part # 550-511K
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This part is legal for sale and use on Uncontrolled (Non-Emissions Controlled) Vehicles.

See Emissions Details
Holley just brought EFI within range


  • Dual Pattern bolt on carburetor replacement, designed to fit 4150 Flange & Spread Bore manifolds - (Spread Bore Sealing Plate Part #9006 is recommended)
  • Throttle body mounted ECU – no extra boxes to mount
  • Supports up to 650hp with Four 100 Lb/Hr Injectors!
  • Only 4 Wiring Connections Required! (Battery +, Battery - , Switched Ignition & RPM)
  • Includes complete fuel system consisting of; 20ft of 3/8” Vapor Guard Fuel Hose, Fuel Pump, Filters, necessary hardware and bulkhead fitting to return fuel into the tank!
  • Internal fuel pressure regulator eliminates the hassle of plumbing an external fuel pressure regulator (Preset to 58.5 PSI)
  • Integrated ignition timing control & coil driver
  • 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!
  • Self-tuning ECU means you don’t have to be a computer/tuning wiz to have EFI!
  • 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 ensures a leak free oxygen sensor installation, with Stainless Steel T-Bolt clamps and a Stainless Steel (Weldable) oxygen sensor flange
  • Patent Pending
Brand Holley Sniper EFI
Emission Code3
Flange StyleDual Bolt Pattern
Fuel Pressure58.5 PSI
Fuel System TypeReturn
Injector Size100 lb/hr @ 58.5 PSI
Inlet / Outlet Size9/16-18 Female O-Ring (AN 6)
MAP Sensor2Bar
Max Horsepower Rating650 Naturally Aspirated
Product TypeSniper EFI 4150
Part Number550-511K

This part is legal for sale and use on Uncontrolled (Non-Emissions Controlled) Vehicles.

The following vehicles are considered Uncontrolled (Non-Emissions Controlled) Vehicles:

  • 1965 and older U.S. manufactured California Certified vehicles
  • 1967 and older U.S. manufactured Federally Certified vehicles
  • 1967 and older Foreign manufactured vehicle

WARNING: It is against the law to install this part on an Emissions Controlled Vehicle

The following vehicles are considered Emissions Controlled Vehicles:

  • 1966 and newer U.S. manufactured California Certified vehicles
  • 1968 and newer U.S. manufactured Federally Certified vehicles
  • 1968 and newer Foreign manufactured vehicle
Quickstart Guide
Quickstart Guide
Instructions for Part# 550-511K
Instructions for Part# 550-511K
Holley EFI Dealers
Do you need a custom kit built for your application? Do you need a system installed and tuned? Click here to find the Holley EFI dealer in your area!
Sniper EFI SD Card Contents
Sniper EFI SD Card Contents

Have a question about this product?

  • Question

    Is there a specific distributor needed to run with the sniper EFI kit?

    By Karl H. on April 15, 2018

    The most basic installation only requires a tach input to operate. This is generally provided by the negative side of your ignition coil. If you are seeking to utilize ignition timing control, then we recommend using one of our Holley EFI Dual Sync Distributors.
  • Question

    Do I need two o2 sensors sense I am running true fuel exhaust ? With the sniper 550-511k kit

    By Leonard H. on April 15, 2018

    The included O2 sensor is all that is needed for our Sniper TBI systems.
  • Question

    I have a 1980 Pontiac Trans Am with the 4.9Liter Turbo. Is this the right system for my vehicle, if not which one is? Thanks

    By Robert V. on August 21, 2019

    Your engine came with a spread bore carb on it from the factory. Unless you have swapped intake manifolds to a 4150 intake. This product would be a better direct bolt-on choice for your intake manifold. Being a boosted engine, it will require some laptop tuning to get the calibration dialed in 100%. The software is free to download and very easy to use. If you would like to try it out before you purchase anything, it can be found here. Go to the below link, and scroll down to Sniper EFI Software.
  • Question

    Does this kit include wiring for the electric fuel pump including relays?

    By Vincent F. on April 27, 2018

    Yes, the fuel pump relay is built into the Sniper EFI Main Harness.
  • Question

    Can the fan/ fans be programmed to come on with the AC ground signal?

    By Jimmy G. on September 15, 2019

    Yes. The ground output will need to trigger a relay to power the fans.
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Some parts are not legal for use in California or other states with similar regulations.