AED offers only the highest Quality Power Valves designed specifically for your Holley performance carburetor. All AED Power Valves are hi-flow units with several vacuum ratings to give you the ultimate in tuning capability. Also available are Alcohol Power Valves designed for the special fuel demands of alcohol. We also offer Power Valve Block off plugs for situations where you don't want to use a power valve. To keep your power valve in tact we provide a special kit to prevent power valve blowout in the case of engine backfires. All AED carburetors come equiped with this kit installed.