Of American origin, the Howmet TX was a sport-prototype very different from the other cars of the late sixties. The engine was in fact a turbine derived from Continental Aviation. The letters TX of the acronym meant "Turbine" and "eXperimental". Two examples of the Howmet were entered in the 1968 24 Hours of Le Mans, for Heppenstal / Thompson and Tullius / Dibley, without being able to finish the race.