Hly Pwr Vlv Block-Off

The Hly Pwr Vlv Block-Off is an essential vacuum line accessory for Holley carburetor enthusiasts and performance builders who need to disable or isolate power valve circuits during tuning or engine modifications. This 1/2-28 threaded plug serves as a direct replacement or upgrade for factory carburetor vacuum ports, allowing you to block off unused or problematic power valve passages without compromising carburetor function. Whether you're running a fully mechanical carb setup, testing jetting without power valve interference, or customizing a vintage or race engine build, this block-off plug delivers a clean, permanent solution.

Manufactured by MR. GASKET, a trusted name in carburetor accessories and performance tuning, the Hly Pwr Vlv Block-Off features a precision-machined aluminum construction with durable gold anodized finish that resists corrosion and matches modern engine bay aesthetics. The 1/2-28 inch thread pitch is the industry standard for Holley power valve ports, ensuring a secure, leak-free fit without modification. An integrated gasket is included to guarantee a reliable seal against carburetor vacuum leaks, eliminating the need for separate sealing material and reducing installation time during carb rebuilds or upgrades.

Street and competition carburetor builders, vintage hot rod restorers, and fuel system tuners benefit most from this precision plug when reconfiguring Holley four-barrel and two-barrel carburetors for manual or fully mechanical operation. Installation is straightforward—simply thread the plug into the 1/2-28 power valve port on your Holley carburetor body, tighten by hand, and verify the gasket seal. Weighing only 0.05 lbs and measuring 3.25 x 0.9 x 5.85 inches, this compact block-off remains discreet in tight engine compartments and integrates seamlessly with standard Holley vacuum line configurations during carburetor assembly or modification.