This 1985-91 Corvette Air Pump Pulley Kit has highly polished aluminum brackets and uses grade 8 bolts. A great item to help get those horses to the rear tires, while allowing the engine to rev even quicker than it does from the factory. Tech Note: For offroad & race use, on dual exhaust cars only. Purchase of new belt locally is required in some installations due to varying pulley sizes installed by GM according to option requirements.