Holley 125-85 Single-Stage Power Valve;

This single-stage standard flow power valve boosts your vehicle's power when pulling heavy loads or at fast speeds. By enhancing the carburetor's response to vacuum forces, the power valve allows an optimal amount of fuel through the carburetor for increased torque and higher speeds. The power valve will open when the engine reaches a vacuum of 8.5 Hg. It has a 90-day warranty for defects in material and workmanship.