AED Performance was founded with one basic premise in mind -- the manufacturing of high quality components at competitive prices. You can see the results of that dedication and focus in their carburetors and components, like these Power Valves. AED offers only the highest quality Power Valves designed specifically for your Holley performance carburetor. Designed to add extra fuel when a richer mix is needed, this is a high flow unit that opens at 8.5 inches of vacuum. Always choose a power valve that is below your lowest manifold vacuum attained while idling in gear.