The Bradley GT was in the middle of its timeline as of 1973. These were officially sold as kit cars, though fully assembled versions could be arranged through the factory. Usually the builder would place these on a second hand Volkswagen Beetle platform but sometimes a Chevrolet Corvair would find itself under a Bradley.
An interesting option was a padded roll bar that you could spec out inside the cockpit. The GT was offered through the 1978 model year. Performance was up to the builder, as the VW aftermarket was, and still is quite sizable.