Made in USA
Sniper EFI XFlow Self-Tuning Fuel Injection System
Product Discontinued
HOLLEYPART NUMBER: 510-550-540

Sniper EFI XFlow Self-Tuning Fuel Injection System

Currently Unavailable

This product is no longer available. Please call customer service for assistance at 1-800-345-4545.

(4) Injector Models
Sniper EFI XFlow Self-Tuning Fuel Injection System
  • 4150 & Spread Bore Flanges
  • 900 CFM
  • Supports Up to 800 N/A HP
  • Forced Induction & Nitrous Compatible
  • Controlled by 3.500 in. Touchscreen
  • (4) 120 lbs./hr Injectors
  • Shiny Finish

    For Troubleshooting Tips setting up your New Holley Sniper EFI System, please see this helpful video from Holley Performance.

    Sniper EFI XFlow Self-Tuning Fuel Injection System Features:

    • Supports up to 800 naturally aspirated HP using (4) 120 lbs./hr Injectors
    • 900 CFM flow rate
    • Compatible with draw-through or blow-through forced induction
    • 2.5 Bar MAP Sensor
    • Integrated ignition timing control
    • Built-in single-stage progressive nitrous controller
    • Adjustable boost control 
    • Programmable target air/fuel ratio at specific boost intervals
    • (3) Programmable 0-5 V sensor inputs for oil, fuel, dome or nitrous pressure sensors
    • (6) Programmable ground outputs
    • (1) +5 V reference output
    • (1) Sensor ground
    • Dual pattern carb flange designed to fit 4150 and spread bore manifolds
    • Throttle body mounted ECU
    • (4) wiring connections required (Battery +, Battery -, Ignition, RPM)
    • High-resolution color touchscreen controller
    • calibration wizard tunes ECU without the use of a computer
    • Genuine Bosch LSU 4.9 wideband oxygen sensor provides realtime fuel map learn
    • OEM-style throttle position sensor and idle air control
    • 2.500 in. clamp-on oxygen sensor kit allows easy integration into older exhaust systems
    • -6 AN Female O-Ring Inlet/Outlet 
    • 200R4, 700R4 TH350 Compatible transmissions

    Installation Notes:

    Sniper EFI XFlow requires an external fuel pressure regulator (sold separately).

    E-85 Fuel not recommended.

    Emissions Note:

    This part is only legal for sale and use on Uncontrolled (Non-Emissions Controlled) Vehicles or on vehicles used solely for the purposes of closed competition racing.

    CLICK THIS LINK FOR IMPORTANT CARB & EPA EMISSIONS INFORMATION ABOUT THIS PART

    • EFI Conversion Suitable for Power Adders & High-Horsepower Engines

      Holley has expanded its line of critically acclaimed self-tuning EFI systems to include the Sniper EFI XFlow. These fuel injection conversion kits are designed to support naturally-aspirated (800 HP) and forced-induction (1375 HP) engines while being compatible with forced-induction applications with up to 21.5 psi of boost. The Self-Tuning ECU makes it an easy, no-hassle way to get the most performance out of your vehicle without the use of a computer. Just answer a few questions about your engine and Sniper EFI XFlow creates a base map, then starts tuning on its own while you drive.


      See More

      Unleash next-level fuel control and drivability with Holley Sniper EFI XFlow Self-Tuning Kits—engineered for high-performance engines demanding more airflow and advanced tuning flexibility. Whether you're running boost, nitrous, or just building serious naturally aspirated horsepower, the Holley Sniper XFlow gives you modern EFI performance with classic carburetor simplicity.

      Delivering up to 900 horsepower worth of airflow, the XFlow throttle body is designed for big power builds without sacrificing everyday drivability. Its 8-injector design supports higher fuel demands, while the self-learning ECU continually refines fueling to match real-world driving conditions—giving you smoother starts, better throttle response, and increased efficiency.

      Perfect for enthusiasts upgrading from traditional carburetors, the Holley XFlow bolts onto most 4150-style intake manifolds and features integrated sensors, a handheld touchscreen for tuning, and advanced ignition control. No laptop tuning required—just a simple setup and go.

      Each Sniper X Flow kit includes everything you need to convert your setup, from fuel injectors and sensors to gaskets and wiring, making installation fast and hassle-free. The system also supports boost and nitrous timing tables, making it ideal for power-adders and performance applications.

      Ready to replace your carb and wake up your engine? Shop Holley Sniper EFI XFlow Self-Tuning Kits at JEGS and enjoy the benefits of modern EFI: power, precision, and reliability—without the tuning headaches.




    Part TypeFuel Injection System
    Product LineHolley Sniper EFI XFlow Self-Tuning Kits
    BrandHOLLEY
    Package Height9.0
    Package Width12.5
    Package Length14.5
    Weight12.5 PG
    Part CategoryPerformance Parts
    Wiring Harness IncludedYes
    Iat Sensor IncludedYes
    Venturi Quantity4
    Intake Manifold IncludedNo
    Calibration Module IncludedYes
    Throttle Body Mounting Flange4-barrel spread bore
    Distributor IncludedNo
    Injection StyleThrottle body
    Iac Motor IncludedYes
    Fuel Pump IncludedNo
    Throttle Body FinishShiny
    Throttle Body IncludedYes
    Metering StyleMass airflow
    Fuel Pressure Regulator IncludedNo
    QuantitySold as a kit
    Injectors IncludedYes
    Tps Sensor IncludedYes
    Fuel Rails IncludedNo
    Ecm IncludedNo
    Oxygen Sensor IncludedYes
    Injector Size (Lbs./Hr.)120
    Part FitmentSemi Universal
    Throttle Body MaterialAluminum
    Airflow Rate (Cfm)900 cfm
    Map Sensor IncludedYes
    Package Qty1
    Package TypeEA
    No Questions
    No Reviews

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