The car's chassis is often described as a wooden monocoque. This was not the first such structure designed and built by Costin. In 1959 he had partnered with Jem Marsh to start Marcos Engineering and produce the timber chassis Marcos GT Xylon that debuted in 1959. In 1965 the Costin-Nathan sports racer was launched, funded by Roger Nathan. And in 1967 the Costin-Harris Protos open wheel car started to be raced by Ron Harris Racing in Formula Two (F2) events, as well as one appearance in Formula One (F1) at the 1967 German Grand Prix joint F1/F2 event at the Nürburgring.