D52 Wilwood calipers(with brake pads). 1958-1964 Chevrolet Impala, Bel Air, Biscayne 2" Drop Spindle 12" Rotor Disc Brake Kit. Our cast iron 2" drop spindles allow you run a large 12" rotor on your Impala, Bel Air or GM equivalent fullsize vehicle and will provide a full 2" drop while also allowing you to run 12" brake rotor for increased braking performance.