Secondary Metering Block

The Holley Secondary Metering Block (HLY134-131) is a critical fuel management component for Holley 4160 carburetors, engineered to regulate fuel delivery on the secondary side of your four-barrel setup. As a carburetor enthusiast or serious engine builder, you understand that precision metering directly impacts throttle response, part-throttle performance, and overall drivability. This metering block controls how much fuel enters the secondary barrels when they open, which is essential for smooth power transitions and avoiding bog or hesitation during acceleration.

Constructed from aluminum with a chromate finish, this secondary metering block delivers corrosion resistance and lightweight durability in engine bay environments. The chromate coating protects against oxidation while maintaining a professional appearance, and the aluminum construction minimizes weight while sustaining the structural integrity required for consistent fuel atomization. Gaskets are included, simplifying installation and ensuring proper sealing without requiring separate purchases. The compact 3.3 x 3.3 x 6.7 inch footprint integrates seamlessly into existing Holley 4160 carburetor assemblies, maintaining OEM-style proportions while supporting reliable fuel metering calibration.

This part is ideal for carburetor rebuilds, restorations, and performance tuning on street rods, classic trucks, and vintage muscle cars equipped with Holley 4160 carburetors. Whether you're replacing a worn metering block during a full carb rebuild or upgrading a fuel delivery system for improved consistency, this OEM-style replacement ensures accurate secondary fuel flow without modification to your existing fuel system. Installation requires basic mechanical knowledge and hand tools; the included gaskets guarantee a leak-free seal when torqued to specification, making this a straightforward upgrade that delivers measurable gains in throttle modulation and engine response.