Frank Kurtis was the son of a Croatian blacksmith who emigrated to America. He turned his talents to dragsters, race boats, land-speed racers and sports cars, as well as the midget racers that launched so many careers. He became the preeminent builder of Indy Cars as the postwar era blended into the fabulous 1950s. In 1952, Popular Mechanics acknowledged Kurtis as 'the country's leading race-car builder;' the following year, Popular Science hailed him as 'the man who has turned out more sports cars than anyone else in the country.'

The Frank Kurtis-engineered single-seater midget race cars proved almost unbeatable on the racing circuit. They were offered in both complete and kit forms that were capable of accommodating Ford's 136 cubic-inch V-8 Flathead engine delivering 60 horsepower and built from 1937-1940. This configuration was particularly effective on the popular URA (United Racing Association) 'Blue' circuit reserved for non-Offenhauser-powered cars. It is believed that Kurtis produced approximately 550 fully assembled Midgets and another 600 in kit form.

Kurtis helped construct the ill-fated front-drive Novi cars that raced at Indianapolis in 1946 and 1947, and then began entering his own cars in 1948. Two years later, driver Johnnie Parsons gave Kurtis his first Indy 500 win, at the wheel of a Kurtis 1000. It would be the first of five Kurtis victories at the Brickyard. His cars would eventually win 54 National Championship races, tying Kurtis for seventh place among Champ Car builders. At one point, the Indy 500 lineup included as many as 23 cars of his manufacture.

The accomplishments of Frank Kurtis and his cars earned him enshrinement in the National Sprint Car Hall of Fame, the Motorsports Hall of Fame of America, and the National Midget Auto Racing Hall of Fame.

The Kurtis Kraft 4000 was introduced in 1951, and it is believed that as many as fifteen examples were constructed, but perhaps closer to twelve examples. They were given a traditional upright design that could be comfortably driven on the bricks at Indianapolis or the dirt tracks of the AAA championship circuit. Many examples campaigned on champ circuits through the early 1960s.

Racing specifications vary but typically include a 96-inch wheelbase with truss-tubular construction, a beam front axle, and a live rear axle. Under the bonnet was a 270 cubic-inch, dual-overhead-camshaft Offenhauser inline four-cylinder engine backed by a two-speed transmission with a low gear for the pits and high gear for the track. Much of the engine's durability was attributed to the incorporation of the cylinder head into the block casting and could endure compression ratios as high as 17:1. At a time when Ferrari and Maserati clung to drum brakes, Kurtis outfitted his single-seater with four-wheel discs.

The single-seater Kurtis KK4000 was a lighter version of its predecessor, the 3000 series. They were sophisticated, durable, and offered predictable handling. One example, now in the collection of the Arizona Open Wheel Racing Museum, ran in AAA-USAC Champ Car events from September 1952 to August 1975.

by Dan Vaughan