Supports Up To 650HP – 3.5 in. Handheld Monitor – Carburetor Styling – Return Fuel System

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SKU: HLY550-870K Categories: ,
Holley’s Sniper Stealth 4150 Master Kit gives you carburetor styling but functions just like the Sniper! A 4150 stealth is a great way to upgrade your ride to fuel injection in a cost-efficient way with just 4 simple connections required. Take your build to the next level and take advantage of improved engine performance, better MPG’s and easier starting. This kit supports up to 650hp naturally aspirated and 600hp boosted with Four 100 Lb/Hr injectors! You don’t have to be a computer wiz or tuning professional to run a sniper kit on your build. Simplicity is what we strive for! Our calibration wizard allows you to just answer a few questions about your engine and the system will begin self-tuning with no laptop required. Use the high resolution 3.5″ full color touchscreen for tuning and gauge displays. The stealth 4150 also includes transmission kick down provisions for GM TH350/400, 200R4/700R4 and Ford C4/C6 applications. The 4150 includes a complete fuel system consisting of all necessary hardware to return fuel into your tank. Additionally, you’re getting a 4.9 wideband oxygen sensor with a leak free oxygen sensor, oem style TPS/IAC, fuel pressure regulator, all Stainless Steel T-Bolt clamps and a Stainless Steel weldable flange. Once you made your conversion to EFI, don’t stop there! Sniper is an Ecosystem! This kit pair’s seamlessly together with Holley’s Sniper Hyperspark Ignition, Fuel System’s, Air Cleaners, Throttle Body & Digital Dash to unlock the full potential of your build. Part # 34-42 is required for a bolt-in installation.


  • Bolt on 4150 Flange Carburetor Replacement
  • 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!
  • Only 4 Wiring Connections Required! (Battery +, Battery – , Switched Ignition & RPM)
  • Supports up to 650hp with Four 100 Lb/Hr Injectors!
  • Throttle body mounted ECU – no extra boxes to mount
  • High Resolution Full Color Touchscreen for Initial Setup, Tuning, and Gauge Displays
  • All of the wiring exits below the rear fuel injector cover, for a completely stealth installation.
  • Timed spark part 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.
  • External fuel pressure regulator required, set to a base pressure of 58.5 PSI, such as 12-886.
  • Integrated ignition timing control
  • The included Genuine Bosch LSU 4.9 Wideband Oxygen Sensor provides real-time 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

Prop65WARNING: These auto parts can expose you to chemicals including phthalates and lead. Installing or using these parts can expose you to other parts containing these chemicals and to engine exhaust, which are known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to