After its success in the previous year, Lotus returned with four works cars and two private entries. It was only a month after Cliff Allison came sixth after the team's auspicious F1 début at the Monaco Grand Prix. For this race, they put at least one car in 4 classes. The new Lotus 15 was designed by Frank Costin and carried several Coventry-Climax engine options: a 2-litre, 1.5-litre or even 750cc (for the affiliated Equipe Lotus France privateer team). Colin Chapman also got Coventry Climax to develop a new 741cc engine based on their 650cc lightweight boat engine. Finally, there were also a pair of older Lotus 11 models to contest the S-1100 class