Holley Carburetor Power Valve Block Off Plug w/ Nylon Reusable Gasket two Plugs and Gaskets 1/2-28 Thread Includes High Quality Reusable Nylon Gasket This Power Valve Plug Will Block The Power Valve From Enriching The Carburetors Main Circuit. In Most Cases You Will Need To Increasing Jet Sizes, we have plenty of sizes available, please check our store. These Work With Holley Model 2300, 4150, 4160 & 4500 Series Holley Carburetors Also Works With Similar Style AED, Quick Fuel, Barry Grant, Street Avenger & Demon Style Carbs |