American financier – they still have those? – David McMahan claims he now retails the world’s quickest cars. McMahan and partner Marlon Kirby have done something rather unoriginal, yet utterly mad, in taking Richard Noble’s brilliant Ultimata GTR and dropping an all-aluminium 7l Corvette engine in it.Three-speed supercar?The pushrod engine has been boosted by dual turbochargers, upping power to a ridiculous 1 177kW. Unsurprisingly, it’s called the Maxximus G-Force in typically understated American parlance.Considering the car weighs only 1 224kg, performance is ridiculous, knocking over 100km/h from standstill in 2.1 seconds, and hitting 160km/h from take-off in only 4.5 seconds. Curiously, with the amount of power on hand, the Maxximus G-Force only has a three-speed sequential gearbox, showing McMahan’s hand at building a car which is stupefying quick to about 200km/h, perfect for track-work, yet not a Veyron chaser. The tall first gear obviously aids traction off the line. An unlikely partnershipMcMahan owned a series of racecars from a young age, including an AC Ace when he was 18 years old. But he soon was distracted from cars by his love of flying machines - building a helicopter when he was only 18, and flying his own plane by the time he was 19. On his way to the Indy 500 McMahan was driven from his private plane to the track by a very enthusiastic limousine driver named Marlon Kirby, a man working odd jobs to make his dream of building the world’s quickest car a reality. An oddly conceived partnership bloomed and now MacMahan and Kirby are charging $3 million a car for their Maxximus G-Force models - we're sure Richard Noble is thrilled.