The Holley Sniper EFI Quadrajet system is a bolt-on spread-bore electronic fuel injection throttle body built specifically to replace the 50+ year old Rochester Quadrajet on classic Chevrolet, GMC, Buick, Oldsmobile, and Pontiac applications — no adapters, sealing plates, or intake manifold swaps required. It carries over the core features of the 4150-style Sniper EFI, including four 100 lb/hr injectors, built-in timing control, and a 3.5" full-color touchscreen, and supports up to 500 horsepower naturally aspirated. It also fits most stock air cleaners and offers multiple fuel inlet configurations for a stock-appearing installation.
Key Features:
- Throttle body-mounted ECU — no separate control box to mount
- Four 100 lb/hr injectors, rated up to 550 HP
- Only 4 wiring connections required for installation
- Integrated ignition timing control
- Transmission kickdown provisions on the throttle lever for TH350, TH400, 200R4, and 700R4
- Universal throttle/transmission kickdown bracket included
- High-resolution full-color touchscreen for setup, tuning, and gauge displays
- Fits most stock Quadrajet air cleaners
- Simple calibration wizard — no laptop required
- Clamp-on oxygen sensor kit included
- Genuine Bosch LSU 4.9 wideband O2 sensor included
- Requires an external fuel pressure regulator
Specifications:
- Throttle Body Type: 4-barrel spread-bore, Quadrajet-style
- CFM Rating: 715
- Throttle Bore: 1.375" primary / 2.00" secondary
- Fuel Pressure: 58.5 PSI
- Maximum Horsepower: 500 HP naturally aspirated
- Injectors: Four 100 lb/hr
- Handheld Included: Yes, 3.5" full-color touchscreen EFI controller
- Oxygen Sensor: Genuine Bosch LSU 4.9 wideband, clamp-on kit included
- Part Number: 550-869
Requires an external fuel pressure regulator, not included in the kit. Designed for classic GM spread-bore Quadrajet applications on Chevrolet, GMC, Buick, Oldsmobile, and Pontiac.
FAQ
Does the Sniper EFI Quadrajet require an intake manifold swap?
No. It bolts directly onto a spread-bore Quadrajet intake with no adapters, sealing plates, or manifold changes needed.
How much horsepower can it support?
It supports up to 500 horsepower naturally aspirated, using four 100 lb/hr injectors.
Do I need a laptop to tune it?
No. It uses a simple calibration wizard through the included 3.5" full-color touchscreen handheld controller — no laptop required.
Will it fit my stock air cleaner?
It's designed to fit most stock Quadrajet air cleaners and offers multiple fuel inlet configurations for a stock-appearing installation.
What oxygen sensor does it use?
A genuine Bosch LSU 4.9 wideband oxygen sensor is included with a clamp-on installation kit.
Does it need an external fuel pressure regulator?
Yes, an external fuel pressure regulator is required and is not included with this kit.
