Ignition systems, charging systems and electrical devices create magnetic pulses that are of the same frequency range as AM radio, resulting in radio interference or noise. Radio noise suppression capacitors divert this noise to ground so it isn't heard through the radio speakers as an annoying buzz or whine.
Note: Used on 1959 Corvettes built after to April 1, 1959. Mounts to ignition shielding bracket on carbureted Corvette or capacitor bracket on fuel injection 1959-1962 Corvettes. On 1966-1967 427 Corvette w/o Transistor Ignition & 1968-1971 Corvette the capacitor mounts on the coil bracket and connects to positive side of ignition coil.