In 1961 Lotus finished second in the Formula 1 team standings behind Ferrari, mainly thanks to Stirling Moss' results with Rob Walker's car, which was an 18 since the new 21 was in the exclusive use of the factory team. Some 18s in use by other private teams got modified 21-style bodies and are normally known as 18/21. A Walker team car was also raced in this configuration and equipped with a V8 Climax engine.