EFI Conversion, Holley, Sniper Stealth 4150, Single 4-Barrel

Universal Sniper Stealth 4150 Four-Barrel EFI Conversion Kit by Holley®

Carburetor-style 4150 EFI with integrated controller and selectable fuel-system package.

This Holley® Sniper Stealth 4150 EFI conversion retains the general appearance of a four-barrel 4150 carburetor while replacing jets and accelerator-pump metering with electronically controlled fuel injection. Its throttle-body-mounted ECU monitors the wideband oxygen sensor and adjusts the fuel map as the engine operates. A 3.5-inch color handheld display provides initial calibration and live readings without a laptop; compatible ignition components can enable timing adjustments. The four-injector, 100-lb/hr standard version supports up to 650 naturally aspirated horsepower; other versions use eight injectors with different ratings that must be matched to the exact selected manufacturer SKU. The factory-style air-cleaner locator, provisions for GM TH350/TH400 and 200-4R/700R4 kickdown linkages and concealed wiring below the rear injector cover help preserve a traditional engine-bay appearance. The system includes a Bosch LSU 4.9 wideband oxygen sensor and clamp-on exhaust sensor adapter. Each assembly uses the 4150 square-bore intake flange; an appropriate high-pressure pump, fuel supply and regulator are required for the base kit, whereas selected master kits include a pump, filters, hose, return fittings and supporting fuel-delivery hardware as specified for that kit. Confirm injector count, horsepower rating, finish and included fuel-system hardware for the specific version selected.

• 4150 square-bore carburetor-style throttle body • Integrated self-learning EFI controller • Wideband O2 feedback and handheld monitoring • 650-HP rating applies to specified four-injector version • Four or eight 100-lb/hr injector configurations vary by SKU • Base or master fuel-system kit options • Confirm selected finish and injector count