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Product Summary

800 CFM CFM, 100 lb/hr @ 58.5 PSI Injector Size

  • Supports up to 650hp naturally aspirated or 575hp on boost with four 100 lb/hr injectors
  • All new design – the #1 EFI Conversion just got better!
  • Only four wiring connections required: Battery+, Battery-, Switched Ignition, and RPM
  • Calibration wizard only requires that you answer a few simple questions about your engine to create a base map and begin self-tuning – No laptop required
  • Supports up to 650hp naturally aspirated or 575hp on boost with four 100 lb/hr injectors

Rebates Available

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Key Specs

MFG. Part #550-511-5AX
BrandHolley Sniper
CFM800 CFM
Injector Size100 lb/hr @ 58.5 PSI
Max Horsepower Rating650
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Need To Know

Quick and Easy Returns

Return Policy

Holley Sniper 550-511-5AX Details


Want to make the switch from the original Sniper EFI to Sniper 2 and don't want to rewire your system? The new Sniper 2 upgrade kits are designed to do exactly that! Included with each Sniper 2 Plug and Play upgrade system is an adapter solution that connects your existing Sniper EFI wiring harness to a Sniper 2 throttle body in minutes. Simply remove your Sniper EFI throttle body from the intake manifold, unplug all connectors, reinstall the Sniper 2 throttle body, and plug the Sniper EFI 2 adapter harness into your existing main harness. Cycle your ignition key, run a fresh wizard on the display of your choice, and enjoy the benefits of Sniper 2 EFI. The #1 EFI conversion system just got better! Introducing Sniper 2 EFI - a self-tuning, easy-to-install, EFI conversion for common 4-barrel (4150 flange) style carburetors. We took everything that we learned from the original Sniper EFI system and added 14 new features that will make your EFI conversion more simple, reliable, and modern. Like all Sniper EFI systems, Sniper 2 is designed to work with the Sniper Ecosystem that includes Hyperspark ignition, complete fuel systems, multiple user interfaces/dash displays, and more. Make your classic drive like a modern fuel injected vehicle, including easy cold starts, smooth drivability, and improved fuel economy! Sniper 2 is designed to be installed at home in your garage with limited tools and the support of Holley's comprehensive installation manual and videos. The user-friendly setup wizard allows you to answer a few simple questions about your engine and the system will begin self-tuning with no laptop or tuning experience required. If you're looking for a high-performance fuel injection system that delivers power, efficiency, and ease of use, look no further than the Sniper 2 EFI.
  • (NEW) “Hidden Harness” wiring harnesses exits from the rear of throttle body for a clean appearance
  • Update your Sniper EFI to the new, improved Sniper 2 in less than one hour!
  • Eliminates the need to rewire your existing Sniper EFI installation - one step, plug and play upgrade to a Sniper 2 throttle body
  • Improve your ride with the benefits of Sniper 2, including wireless connectivity (coming late 2023), smoother throttle feel, improved RF interference resistance, hidden wiring harness and more
  • Four total kits available – polished and black, with or without external fuel pressure regulator (required for Sniper 2)
  • Reuses existing coolant temperature and wideband oxygen sensors
  • All new design – the #1 EFI Conversion just got better!
  • Supports up to 650hp naturally aspirated or 575hp on boost with four 100 lb/hr injectors
  • Next generation ECU features improved RF noise and interference resistance (stands up to old car wiring, noisy alternators, faulty plug wires)
  • Redesigned throttle shaft and plate geometry for a smoother throttle feel
  • Sniper 2 is Part of the Sniper EFI Complete Ecosystem
  • Sniper 2 is compatible with the complete Sniper EFI Ecosystem that includes plug-n-play Hyperspark Ignition systems (coil, ignition box and distributor), fuel systems (fuel lines, fuel pump hangers), multiple displays and more
  • Available with fuel system kits: that include an adjustable external regulator, fittings, and a 3’ section of fuel hose, allowing you to easily mount your regulator in the engine bay
  • Additional Features
  • (NEW) Integrated transmission kick down provisions for GM TH350/400, 200-4R/700R4 and Ford C4/C6 applications
  • (NEW) “Hidden Harness” wiring harnesses exits from the rear of throttle body for a clean appearance
  • (NEW) Inputs and outputs consist of: 2x Ground Inputs, 2x Ground Outputs, 1x TPS output (0-5v), and 1x Tach Output
  • (NEW) Redesigned injector connector for improved reliability
  • (NEW) Onboard contactless magnetic TPS sensor ensures an accurate TPS reading
  • (NEW) Next Generation mil-spec style M8 positive lock connector for CAN1 and CAN2 provides the latest in CAN bus technology for a simple yet robust connection
  • (NEW) Cast-in fuel crossover from the primary to secondary fuel rail
  • (NEW) Sniper 2 throttle bodies are serialized in house, which provides each unit a birth certificate for an improved customer service and warranty experience in the event of any unit needing to be inspected
  • Patent Pending
  • Rebates

    Holley IRS Sale 2026

    Save 10% instantly on select products across the Holley family of performance brands during the annual Holley I.R.S.Tax Sale. Instant rebate period has been extended and now runs from February 17, 2026 through April 19, 2026.

    CARB Warning

    For use on pre-1966 vehicles only

    Emissions warning: this part only legal for sale or use in California if installed in vehicles model-year 1965 or older; motorcycles model-year 1977 or older; or off-highway recreational vehicles (such as off-road motorcycles and all-terrain vehicles) model-year 1996 and older. ++any other use renders the vehicle tampered and not legal for use on California public highways (any public street or roadway, public dirt road, public park, or publicly maintained right of way open to the use of the public for vehicular travel). Violations subject to $37,500 penalty per violation per vehicle, revocation of registration, loss of use on California public right of ways, and proof of correction for tampering there are similar restrictions and penalties under federal law and the laws of all other states with penalties under federal law of up to approximately $45,268 per tampered vehicle and/or engine.

    Holley Sniper 550-511-5AX Specifications

    KEY SPECS
    MFG. Part #550-511-5AX
    BrandHolley Sniper
    CFM800 CFM
    Injector Size100 lb/hr @ 58.5 PSI
    Max Horsepower Rating650
    GENERAL
    User TunableYes
    Self TuningYes
    Injectors IncludedYes
    Intake Manifold IncludedNo
    Fuel Pump IncludedNo
    Fuel Pressure Regulator IncludedNo
    Distributor IncludedNo
    FinishCeramic
    Overall Height3.28"
    GTIN Code00090127864494
    Sold in QuantityEach
    Customer Impersonation Script