The Type 57 and 57C are recognised as being the most sporting of all non-racing Bugattis. The T57/57C was an entirely new design heavily influenced by Jean Bugatti, son of founder Ettore. Between 1934 and the outbreak of World War II, more than 680 examples are estimated to have been produced in various body styles. The vehicle centred around refinement while focusing on the engineering values that had made Bugatti successful.
During his ownership of chassis 57715, Roberts upgraded the engine in this Type 57 to supercharged Type 57C specification. The modification was a popular one, and many owners actually had the Bugatti factory itself perform the conversion. However, Bugatti was long out of business when Roberts decided to have his car’s powertrain upgraded in 1964. Accounts noted that the supercharger was quiet and provided between three to four pounds of boost pressure by running at 1.17 times crankshaft speed.
135 bhp, 3,257 cc twin overhead cam inline eight-cylinder engine, four-speed gearbox, solid axle and semi-elliptic leaf spring front suspension, solid axle and quarter elliptic leaf spring rear suspension, four-wheel drum brakes. Wheelbase: 130".

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