The 4150 Sniper Stealth Master Kit converts a carbureted 4150-flange engine to self-tuning fuel injection with classic carburetor styling. Four 100 lb/hr fuel injectors support up to 650 HP naturally aspirated or 600 HP under forced induction, and the throttle-body-mounted ECU handles fuel map self-learning and ignition timing control. This master kit includes the complete fuel system components needed for installation.
Key Features:
- Bolt-on 4150-flange carburetor replacement
- Throttle body mounted ECU — no extra boxes to mount
- Four 100 lb/hr fuel injectors, up to 650 HP support
- Includes high-pressure fuel crossover line
- Complete fuel system: external fuel pressure regulator preset to 58.5 PSI
- 20 ft. of 3/8 in. Vapor Guard fuel hose
- Fuel pump, filters, and necessary installation hardware included
- Bulkhead fitting to return fuel to the tank
- All wiring exits below the rear fuel injector cover
- Self-tuning calibration wizard — no laptop required
- 3.5 in. high-resolution full-color touchscreen for tuning and gauge displays
- Integrated ignition timing control
- Transmission kick-down provisions for GM TH350/400, 200R4/700R4 and Ford C4/C6
Specifications:
- Product Type: 4150 EFI Throttle Body Master Kit
- Flange: 4150
- CFM: 870
- Base Fuel Pressure: 58.5 PSI
- Finish: Shiny
- Injectors: 4 x 100 lb/hr
- Horsepower Support: Up to 650 HP naturally aspirated, up to 600 HP forced induction
- Fuel System Included: Regulator, 20 ft. Vapor Guard hose, pump, filters, hardware
- Transmission Kick-Down: GM TH350/400, 200R4/700R4, Ford C4/C6
- Part Number: 550-870K
Holley part # 34-42 is required for a bolt-in installation.
FAQ
What's included in the 550-870K Master Kit that isn't in the base 550-870?
The Master Kit adds a complete fuel system: an external fuel pressure regulator preset to 58.5 PSI, 20 ft. of 3/8 in. Vapor Guard fuel hose, a fuel pump, filters, necessary hardware, and a bulkhead fitting to return fuel to the tank.
How much horsepower can this kit support?
Up to 650 HP naturally aspirated or up to 600 HP on forced induction with its four 100 lb/hr injectors.
Do I need additional parts for a bolt-in installation?
Holley part # 34-42 is required for a bolt-in installation.
Do I need a laptop to tune this system?
No. It uses a self-tuning calibration wizard and an onboard 3.5 in. touchscreen for setup and gauge display — no laptop required.
What transmissions does the kick-down feature support?
GM TH350/400 and 200R4/700R4, along with Ford C4/C6 transmissions.