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#425550870K
Holley Sniper 550-870K Stealth 4150 EFI Master Kit, Shiny
- Designed to be a direct bolt-on 4150 flange carburetor replacement
- Includes a throttle body mounted ECU with no extra boxes to mount
- It is able to support up to 650hp with Four 100 Lb./Hr. Injectors!
$1,618.95
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$1,799.95
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Product Summary
Universal Fit, Throttle Body Injection Style, Polished
- Designed to be a direct bolt-on 4150 flange carburetor replacement
- Includes a throttle body mounted ECU with no extra boxes to mount
- It is able to support up to 650hp with Four 100 Lb./Hr. Injectors!
- Includes a high-resolution full color touchscreen for initial setup, tuning, and gauge displays
- The self-tuning ECU means you don’t have to be a computer/tuning wiz to have EFI
Rebates Available
See rebate detailsKey Specs
| Injection Style | Throttle Body |
| CFM | 870 CFM |
| Injector Size | 100 lb/hr @ 58.5 PSI |
| Max Horsepower Rating | 650 |
| ECM Included | Yes |
Need To Know
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Holley Sniper 550-870K Details
The Sniper Stealth 4150 EFI system from Holley features 4, 100LB/HR Fuel Injectors capable of supporting up to 650 HP naturally aspirated or 600 HP on forced induction applications. The Sniper Stealth 4150 ECU is capable of fuel map self-learning and ignition timing control, improving idle stability, drivability, and wide-open throttle horsepower! Did we mention that the Stealth 4150 also includes transmission kick down provisions for GM TH350/400, 200R4/700R4 and Ford C4/C6 applications?
Master Kits include complete fuel system with an external fuel pressure regulator preset to 58.5psi, 20ft of 3/8" Vapor Guard Fuel Hose, Fuel Pump, Filters, necessary hardware and bulkhead fitting to return fuel into the tank!
Features:
- Bolt-on 4150 Flange Carburetor Replacement
- Throttle body mounted ECU – no extra boxes to mount
- Supports up to 650hp with Four 100 Lb/Hr Injectors!
- Includes high-pressure fuel crossover line
- All of the wiring exits below the rear fuel injector cover, for a completely stealth installation.
- Timed spark port for vacuum advanced distributors located under the front fuel bowl, for easy access to the distributor.
- Air entry is machined to fit most stock-style air cleaners with air cleaner locator provisions.
- Only 4 Wiring Connections Required! (Battery +, Battery - , Switched Ignition & RPM)
- External fuel pressure regulator required, set to a base pressure of 58.5 PSI, such as12-882.
- Integrated ignition timing control
- 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 for 2.25" exhaust ensures a leak-free oxygen sensor installation, with Stainless Steel T-Bolt clamps and a Stainless Steel (Weldable) oxygen sensor flange
- Available in 3 finishes: Shiny (550-870K), Black (550-871K), and Gold (550-872K)
Charts
Rebates
Holley Fuel Up Spring Savings Event 2026
Save 10% instantly on select products across the Holley family of performance brands during the annual Holley Fuel Up Spring Savings Event 2026. Instant rebate period runs from March 30, 2026 through April 19, 2026.
Guides & Documents
CARB Warning
For race/ off road use or for use on pre-1966 vehicles.
CARB Warning
For race/ off road use or for use on pre-1966 vehicles.
Holley Sniper 550-870K Specifications
Holley Sniper 550-870K Specifications
| KEY SPECS | |
|---|---|
| MFG. Part # | 550-870K |
| Brand | Holley Sniper |
| Injection Style | Throttle Body |
| CFM | 870 CFM |
| Injector Size | 100 lb/hr @ 58.5 PSI |
| Max Horsepower Rating | 650 |
| ECM Included | Yes |
| GENERAL | |
| Carburetor Flange Type | 4-Barrel Square Bore |
| User Tunable | Yes |
| Self Tuning | Yes |
| Injectors Included | Yes |
| Intake Manifold Included | No |
| Metering Style | Speed density |
| EGR | No |
| Throttle Body Included | Yes |
| Throttle Body Material | Cast Aluminum |
| Throttle Body Finish | Polished |
| Venturi Quantity | 4 |
| Fuel Pump Included | Yes |
| Fuel Rails Included | No |
| Calibration Module Included | Yes |
| Wiring Harness Included | Yes |
| Fuel Pressure Regulator Included | Yes |
| Distributor Included | No |
| MAP Sensor Included | Yes |
| IAC Motor Included | Yes |
| IAT Sensor Included | Yes |
| TPS Sensor Included | Yes |
| Finish | Polished |
| Use with Power Adder | Yes |
| GTIN Code | 090127078396 |
| Sold in Quantity | Kit |