A vacuum operated antenna was available as a factory accessory item for the 1949-50 cars but I'm not aware of it being available for the 51-55 Kaisers. They are very rare and expensive when they do appear for sale. KF never offered an electrically operated antenna, although I'm sure someone's figured out how to retrofit a modern unit.
If you decide to use a manual unit, 1957-59 Chevy truck antennas are a very close match to the KF unit
