Dan Gurney had tested Mickey Thompson's rear-engined Champ Car for the 1962 Indianapolis 500 and, convinced that the layout was a potential race-winner, approached Colin Chapman of Lotus with the idea of building a similar car for the 1963 Indianapolis 500. Chapman attended the 1962 race and Gurney then arranged a meeting with Ford to source a suitable engine. Later that year, Chapman had Jim Clark and Lotus mechanics Jim Endruweit and Dick Scammell sent to Indianapolis after the 1962 United States Grand Prix to do some testing with the race-winning Lotus 25. Results proved positive, and construction was started on a new car, the type 29. Based on the 25, it was a very similar car which differed principally in featuring a 4195 cc (255ci) Ford V8 with Weber carburettors producing 376 bhp (281 kW) through a Colotti T.37 gearbox. It was slightly larger all round than the 25 and was fitted with offset suspension and Dunlop (front) and Halibrand (rear) knock-off wheels to facilitate rapid pit stops. Three cars were built in all; the first being essentially a development prototype, after which two cars were built for Clark and Gurney.