FQRANBO Adjustable Fuel Pressure Regulator 12-804 — 1-4 PSI, Gauge, 3/8" NPT

FQRANBO 12-804 is an adjustable fuel pressure regulator with an integrated gauge, designed to stabilize and fine-tune carbureted fuel delivery between 1 and 4 PSI for Holley and Edelbrock setups.

When upgrading or maintaining a carbureted engine, consistent low-range fuel pressure matters for idle quality, throttle response, and carburetor calibration. The 12-804 provides a compact, metal-and-ABS solution with a 3/8" NPT gauge port and a 0.220-inch restrictor orifice to control flow to Holley and Edelbrock carburetors. Built with a regulating knob and an improved 1 PSI-scale gauge, it helps you dial in fuel pressure precisely while resisting heat and corrosion in under-hood conditions.

How does the 12-804 control fuel pressure on carbureted engines?

The regulator modulates the flow from the fuel pump to the carburetor using an internal pressure-stabilizing mechanism and an adjustable knob. The built-in restrictor helps maintain steady low-range pressures appropriate for Holley and Edelbrock carburetors.

• Adjustable 1–4 PSI range tailored for many street and performance carb setups
• 0.220-inch (7/32") restrictor orifice to stabilize flow
• Internal stabilizer reduces pressure spikes and oscillations
• Fine-tune with the external regulating knob for consistent delivery

What fittings and ports does this regulator include?

The 12-804 features a 3/8" NPT gauge port and a 1-in/2-out configuration that simplifies plumbing and gauge installation. The port layout accommodates a pressure gauge for real-time monitoring and allows tidy routing to carburetor feed lines.

• 3/8" NPT gauge port for easy pressure reading and adjustment
• One inlet and two outlet paths to match common carburetor feed setups
• Compact footprint to fit tight engine bays and retrofit applications
• Compatible connection standard for many aftermarket fittings and adapters

How durable and serviceable is the FQRANBO 12-804 under the hood?

Constructed primarily from metal with ABS components, this regulator resists heat, pressure, and corrosion typical in engine compartments. It includes a hexagon socket nut for installation; removing the nut during setup allows adjustment, then reseating prevents leaks and preserves calibration.

• Metal body with ABS parts designed for high-temperature environments
• Corrosion-resistant surfaces for long-term reliability
• Hexagon socket nut design to lock adjustments and reduce leak risk
• Service note: back out nut to adjust, then secure to avoid misadjustment

What improvements does the upgraded gauge bring?

The pressure gauge now uses a refined scale with 1 PSI increments, replacing the coarse 20 PSI span of earlier designs. This finer resolution reduces misadjustment risk and helps you achieve repeatable pressure settings for tuning and diagnostics.

• Minimum scale step of 1 PSI for precise calibration
• Better visibility of small pressure changes during tuning
• Faster diagnostics for unstable or fluctuating pressure readings
• Customer support available for display anomalies or instability

Who is this for? The FQRANBO 12-804 fits drivers, mechanics, and hobbyists who run Holley or Edelbrock carburetors and need dependable low-range pressure control. It’s ideal for street-performance builds, restoration projects, or any carbureted vehicle where smoother idle, reliable throttle response, and easier tuning are priorities. If you plan to monitor pressure closely or retrofit a modern gauge to an older carb setup, this regulator gives a compact, serviceable solution that balances precision and durability.