Carburetor Power Valve Block Off Plug With Reusable Gasket Replaces for Holley Specs: *Sold as Each *Includes High Quality Reusable Nylon Gasket & Performance Viton Coated Non Stick Gasket * Works With All Fuels Including Gas, Race Fuel, E85, Alcohol *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 2300, 4150, 4160 & 4500 Series Carburetors *These Parts Will Come In Bulk Style Bag Packaging