1957 Kurtis 500X

The Kurtis Kraft Company was founded by designer Frank Kurtis. They were first and foremost a builder of race cars although it also built a few road-going models. In the mid-1950s, the Kurtis 500X was built with a total of six to twelve examples built. They were road racing specials with a Kurtis-designed (and built) space frame with an all-alloy body. In comparison to its predecessor, the 500S, which had a ladder frame, the 500X weighed around 200 pounds less than the 500S. The 500X had a live axle suspension with torsion bars in the front and a solid axle in the back.

The first 500X example was SX-1 and was built for Jack Hinkle. Hinkle installed a four-cylinder Offenhauser midget engine and used it to compete in the smaller displacement race categories of its day. The second car was SX-2 which was built for Albert Hoskins and Mickey Thompson. That car had a 389 cubic-inch supercharged Cadillac V8 engine. The third car was SX-3, built for Bill Murphy, and fitted with a 322 cubic-inch Buick V8. It was originally given Stromberg 97 carburetors but this was later switched with a 324 B-8 Hilborn fuel injection system. The car proved to be a fast and fierce competitor, scoring 18 class victories with 9 overall wins in 31 starts.

The fourth 500X produced was chassis number SX-4. It was given a Chevy powerplant. The next car was the Ak Miller modified car used in the construction of his Caballo II. The plan was to prepare the car for the Carrera Panamericana, but the event was canceled after the 1954 race. Nonetheless, construction continued. The car had a rear axle from Lincoln, a Thornton limited-slip differential, twelve-inch drum brakes, a Micro-lock double master cylinder, and a Moss four-speed gearbox from a Jaguar Mk. Vii. The all-aluminum body was designed by Jack Sutton of Hollywood, California.

Powering the Caballo II was a 392 cubic-inch Chrysler Hemi V8 engine offering 400 horsepower. Upon completion, the car was entered in the 1957 edition of the Mille Miglia. After 300 miles, the Caballo II broke down due to a cracked brake drum. After the Mille Miglia, the car was taken to Bonneville in August of 1957 where it achieved an impressive 176 miles per hour. It later competed in the Los Angeles Times Grand Prix at Riverside in 1958. During a practice session, the car was damaged in a crash and was unable to start the race.

The sixth car produced may have been the Mistral special.

by Daniel Vaughan | Sep 2014