Holley Sniper EFI

Holley Sniper EFI — Self-Tuning Throttle Body Injection for Classic & Performance Engines

The Holley Sniper EFI system is the most straightforward carb-to-EFI conversion available for classic and performance V8 applications. Designed to bolt directly onto a standard four-barrel intake manifold in place of a carburetor, the Sniper delivers modern fuel injection performance — reliable cold starts, consistent fuel delivery across all temperatures, and improved throttle response — without requiring a standalone ECU, custom wiring harness, or professional tuning to get the engine running correctly.

Self-Learning Fuel Management

The Sniper's built-in wideband O2 sensor and self-learning ECU continuously monitor exhaust gas composition and adjust fuel delivery in real time to maintain the correct air/fuel ratio across all operating conditions. From cold start enrichment through wide-open-throttle fueling, the Sniper adapts to the engine's specific requirements without manual jet changes, needle adjustments, or dyno time. For builders who want EFI performance without EFI tuning complexity, the Sniper delivers exactly that.

The integrated touchscreen display provides real-time monitoring of AFR, coolant temperature, throttle position, fuel pressure, and battery voltage — giving the driver immediate visibility into engine operating conditions without a separate gauge cluster or data logger.

Sniper System Variants

Holley offers the Sniper in multiple configurations to match different build requirements and aesthetic preferences. The standard Sniper 2300 and 4150 units are available in polished aluminum and black finishes for builds where the EFI system is meant to be visible and purposeful-looking. The Sniper Stealth 4150 and Stealth Quadrajet designs replicate the visual profile of a carburetor or factory Quadrajet, making the EFI conversion invisible to casual observers —olean solution for show cars and period-correct builds where modern technology needs to stay hidden.

The Sniper 2 series represents the latest generation of the platform, with an updated ECU, improved self-learning algorithms, and expanded compatibility for a wider range of engine combinations and operating conditions.

Fuel System Requirements

The Sniper EFI system requires a fuel pump capable of maintaining 58–60 PSI — the OEM mechanical pump on most carbureted engines cannot meet this requirement and must be replaced with an electric unit. Holley offers complete returnless fuel system kits that include an in-tank pump, sending unit, and all required fittings for a clean installation without a return line. For builds retaining the original fuel tank, inline electric pump options are available with the correct pressure output for Sniper operation.

Common Applications

The Holley Sniper EFI is compatible with any engine running a standard square-bore four-barrel intake manifold, covering Small Block and Big Block Chevy, GM LS with appropriate adapter, Small Block and Big Block Ford, Chrysler/Mopar V8, and Pontiac applications. The Sniper Quadrajet variant fits spread-bore manifolds used in GM applications from the 1970s and 1980s. Engine displacement, camshaft profile, and compression ratio do not limit Sniper compatibility — the self-learning system adapts to the engine combination.

Installation Notes

Sniper EFI installation requires an electric fuel pump at the correct pressure, a wideband O2 sensor bung in the exhaust, a coolant temperature sensor, and a 12V ignition-switched power source. The system connects to the distributor for RPM signal on most applications. Initial startup involves entering basic engine parameters — displacement, number of cylinders, and idle RPM target — after which the Sniper begins its self-learning process. Most engines are running correctly within the first few drive cycles without additional adjustment.

Shop Holley Sniper EFI at Ozkonic Kustomz

Browse the full Holley Sniper EFI lineup below — standard, stealth, and Sniper 2 systems, fuel system kits, and accessories. If you need help selecting the right Sniper variant for your engine and build goals, reach out. It's the cleanest path from carburetor to EFI, and we'll help you get there right.

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