Sniper 2 EFI is Holley's self-tuning fuel injection conversion for classic 4150-flange carbureted engines, built to bolt on in place of a 4-barrel carburetor and deliver modern cold starts, drivability, and fuel economy. A guided setup wizard walks through a few questions about the engine and the system begins self-tuning from there — no laptop or tuning experience required. This configuration includes the optional Power Distribution Module (PDM), which consolidates the core EFI and ignition wiring into a single connection point, and pairs with the 3.5" handheld for setup, tuning, and gauge display.
Key Features:
- Self-tuning ECU with a calibration wizard that builds a base map from a few engine questions — no laptop required
- Bosch LSU 4.9 wideband oxygen sensor included for real-time fuel map learning
- Optional Power Distribution Module (PDM) consolidates EFI and ignition wiring into one connector
- Onboard contactless magnetic TPS sensor for accurate throttle position readings
- Integrated transmission kickdown provisions for GM TH350/400, 200-4R/700R4, and Ford C4/C6
- Plug-and-play HyperSpark distributor support built into the main harness for integrated timing control
- Cast-in fuel crossover between primary and secondary fuel rails
- Only four wiring connections required: Battery+, Battery-, Switched Ignition, RPM
- Compatible with the Sniper EFI ecosystem: HyperSpark ignition, fuel systems, and multiple gauge/display options
- Choice of tuning interfaces: 3.5" handheld, 5" digital dash, or Bluetooth dongle for iOS/Android
- Redesigned injector connector and throttle shaft/plate geometry for improved reliability and throttle feel
- Clamp-on oxygen sensor kit with stainless steel T-bolt clamps and weldable O2 flange included
- Next-generation ECU with improved RF noise and interference resistance
- Each throttle body is individually serialized for warranty and service tracking
- Adapters for other ignition types sold separately (558-329 CD Box to Sniper 2, 558-330 MSD Pro-Billet/Crank Trigger to Sniper 2)
Specifications:
- Flange Style: 4150
- CFM: 800
- Max Horsepower: 650 naturally aspirated, 575 on boost with four 100 lb/hr injectors
- Injector Size: 100 lb/hr @ 58.5 PSI
- Fuel Pressure: 58.5 PSI
- Fuel System: Not included with this kit
- MAP Sensor: 2-bar
- Power Distribution Module: Included
- User Interface: 3.5" handheld
- Inlet/Outlet Size: 9/16-18 female O-ring (AN 6)
- Finish: Shiny
- Transmission Compatibility: All (kickdown provisions for GM TH350/400, 200-4R/700R4, Ford C4/C6)
- Warranty: Two-year standard, extended with product registration
- Part Number: 550-510-3PX
Nitrous control is not supported in the Sniper 2 EFI software. A separate complete fuel system (hose, pump, regulator, filters, and bulkhead fitting) is available and sold separately for this kit.
FAQ
Does the 550-510-3PX include a fuel system?
No, this kit does not include a fuel system — hose, pump, and regulator are sold separately as a complete fuel system kit.
What horsepower does this kit support?
Up to 650 HP naturally aspirated, or 575 HP on boost with the included four 100 lb/hr injectors.
Does Sniper 2 support nitrous control?
No, nitrous control is not supported in the Sniper 2 EFI software.
What is the Power Distribution Module (PDM)?
An optional accessory included with this kit that consolidates the core EFI and ignition wiring into a single, easy-to-use connection point.
Do I need a laptop to tune this system?
No. The calibration wizard on the 3.5" handheld asks a few questions about the engine and builds a base tune, then the system self-tunes from there.
What transmissions does this kit support kickdown for?
GM TH350/400 and 200-4R/700R4, plus Ford C4/C6.
