The answer to this is perhaps quite surprising, and that the platform is still in use.
The Thunderbird 3rd Gen from 1961-1963, shares the platform with the Ford Falcon (and by inference the Mercury Comet). The platform although slightly modified to take an independent rear end is still used by the Australian Ford Falcon.
The Falcon has been built on a continuous basis since 1960 with essentially the same platform. It became famous worldwide when a Ford XB Falcon Hardtop became the Interceptor in the Mad Max series of movies.