Description
High-Performance AVS2 Series 650CFM Carburetor
The iFJF 1906 4-Barrel Carburetor brings legendary AVS2 performance technology to your engine build. Featuring the advanced annular flow booster design, this 650 CFM carburetor delivers exceptional fuel atomization for crisp throttle response and consistent power delivery. Whether you're upgrading a street cruiser, building a restomod, or preparing for weekend track days, the AVS2 platform provides the tunability and reliability that performance enthusiasts demand. The satin finish adds a premium look that complements any engine bay while providing enhanced corrosion resistance.
Annular Booster Technology
The defining feature of the AVS2 series is the annular discharge booster ring, which positions multiple fuel discharge ports around the entire circumference of each booster venturi. This design creates a finer fuel mist than traditional single-point boosters, resulting in more complete combustion, improved fuel economy at cruising speeds, and noticeably sharper throttle response. On the dyno, annular boosters have been shown to improve mid-range torque by 5-10 lb-ft compared to equivalent down-leg booster designs on a typical 350 CID small block.
Vehicle Compatibility
| Engine Family |
Displacement |
Typical Vehicles |
| Chevrolet Small Block V8 |
305 / 327 / 350 / 383 / 400 CID |
Camaro, Chevelle, Nova, Corvette, C10 Truck |
| Ford Small Block V8 |
289 / 302 / 351W CID |
Mustang, Fairlane, F-100, Bronco |
| Mopar Small Block |
318 / 340 / 360 CID |
Dart, Duster, Charger, Challenger |
| AMC V8 |
304 / 360 / 390 CID |
Javelin, AMX, Jeep CJ/FSJ |
| Pontiac V8 |
326 / 350 / 389 / 400 CID |
Firebird, GTO, Grand Prix |
Technical Specifications
| Specification |
Detail |
| CFM Rating |
650 |
| Barrels |
4-Barrel |
| Mounting Pattern |
Square Bore (4150-style) |
| Choke Type |
Electric (12V) |
| Booster Type |
Annular Discharge |
| Fuel Inlet |
3/8" NPT |
| Secondaries |
Vacuum-Operated (Adjustable Air Valve) |
| Finish |
Satin Aluminum |
| Part Number |
1906 |
| SKU |
FJ-CBRT-1906 |
Key Features
- 650 CFM airflow rating - optimized for 300-400+ HP street performance engines
- Annular discharge boosters for superior atomization and throttle response
- Electric choke with fast-idle cam for reliable cold starts
- Adjustable vacuum secondary air valve - tune secondary engagement without removing carburetor
- Two-piece cast aluminum body with satin finish
- Compatible with both manual and automatic transmissions
- Accepts standard 5-1/8" air cleaner flange
Frequently Asked Questions
Q: What is the CFM rating and what engines does it support?
A: The iFJF 1906 is rated at 650 CFM, making it ideal for small-block V8 engines between 305 and 400 cubic inches. It is perfectly suited for 327, 350, 383, and 400 CID engines in street performance and mild racing applications.
Q: What does the annular booster design do?
A: The annular discharge booster design provides superior fuel atomization compared to traditional down-leg boosters. This results in improved throttle response, better fuel economy at cruise, and more consistent air-fuel mixture across all RPM ranges.
Q: Does this carburetor come with an electric choke?
A: Yes, the iFJF 1906 features an integrated electric choke for reliable cold starts. Simply connect to a 12V ignition-switched power source and the choke will automatically adjust based on engine temperature.
Q: Is this a square bore or spread bore carburetor?
A: This is a square bore (4150-style) carburetor designed to bolt directly onto square bore intake manifolds. It can also be used with spread bore manifolds using an adapter plate (sold separately).
Q: What is the satin finish and why does it matter?
A: The satin finish is a premium aesthetic treatment that provides a semi-gloss, non-reflective surface. It resists fuel stains and corrosion better than raw aluminum while maintaining a classic performance look that complements any engine bay.
Q: Is tuning required out of the box?
A: The carburetor comes with baseline calibration suitable for a typical 350 CID engine at sea level. Minor adjustments to idle mixture screws, accelerator pump, and possibly jet changes may be needed based on your specific engine combination, elevation, and performance goals.
Q: What makes this different from the standard AVS series?
A: The AVS2 series features the upgraded annular flow booster design, improved fuel metering circuits, and a revised air valve system that provides more precise secondary engagement compared to the original AVS design, resulting in smoother power delivery and better mid-range torque.
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