Primary Metering Block

The Holley Primary Metering Block (134-128) is the core fuel regulation component for Holley 4160 carburetors, engineered to precisely control fuel flow to the main jets during primary circuit operation. This aluminum metering block features chromate protection against corrosion and arrives complete with gaskets, eliminating the need for separate purchases when rebuilding or servicing your carburetor.

As the central control point for fuel delivery, the metering block houses the needle and seat assembly, fuel inlet passages, and primary jet bosses. The chromate finish provides long-lasting protection in engine bay environments where moisture and heat accelerate corrosion of bare aluminum. The included gasket set ensures proper sealing during installation, maintaining fuel system integrity and preventing internal leakage that would compromise carburetor tuning and engine performance.

Carburetor rebuilding, restoration, and high-performance tuning all require replacement or servicing of the metering block to restore proper fuel metering characteristics. Whether you're refreshing an original 4160 installation, upgrading fuel delivery for modified engine packages, or restoring a classic hot rod, this component must function precisely to maintain correct air-fuel ratios across the primary operating range. The Holley 134-128 is the OEM-equivalent specification block trusted by engine builders and enthusiasts for dependable carburetor performance.