Taking cues from Brabham's Formula One special, and through evolution of the Formula Three curved tube chassis design, Maddock produced a new Formula Two design for 1956: the Cooper T41. He developed this the subsequent year into the Mark II, or Cooper T43, model. Where the 1956 car had been developed for Climax's "FWB", this 1957 car was intended for Climax's new "FPF" four-cylinder engine. While the "FWB" was a development of a pump engine adapted for automobile use, the "FPF" was a bespoke, dry sumped racing design. Even in Formula Two form Maddock's lightweight cars could produce strong performances against more powerful machinery, but the true potential of the design was shown when Rob Walker Racing decided to build a T43 with an enlarged 1964 cc "FPF" engine – and the works entered it for the 1957 Monaco Grand Prix. Driver Jack Brabham unfortunately managed to write the chassis off in practice, but the engine was transferred to another T43 present for the Formula Two race and Brabham managed to qualify 13th for the 16 car race. In the race itself Brabham climbed as high as third place, behind the Maserati 250F of Juan Manuel Fangio and the Vanwall of Tony Brooks, before the little car's fuel pump failed on its 100th lap. Determined to finish Brabham pushed the car from the tunnel, the full distance of the Monaco marina, to the finish line. He was sixth, only one place out of the points, but better was to come.