650-850 CFM Secondary Metering Block

The Advanced Engine Design 650–850 CFM Secondary Metering Block is a precision carburetor component designed for builders and mechanics working with four-barrel carburetor systems. This block is essential for managing fuel distribution during the transition from primary to secondary venturi operation, making it ideal for applications such as street machines, bracket racers, and high-performance crate engine builds.

Engineered for precision, this metering block regulates fuel flow through carefully drilled orifices and metering rods that adjust according to engine load and airflow demand. With a capacity of 650 CFM for conservative fuel supply and up to 850 CFM for more aggressive setups, it accommodates a range of engine configurations and performance needs. The compact aluminum construction measures 2.65 x 1.75 x 4.3 inches and weighs 0.89 lbs, ensuring a seamless integration into standard carburetor bowls.

This secondary metering block is particularly beneficial for experienced carburetor tuners who require consistent fuel staging across the RPM band. By preventing lean-out hesitation or overfueling, it enhances engine performance and reliability. Whether tuning for street use or competitive racing, this metering block is a critical component for optimizing fuel delivery.