The Vallelunga is commonly acknowledged as DeTomaso Automobili's first production model. Its name comes from a race course in Italy, and its mid-engined chassis design from various DeTomaso open wheel-racers. The first Vallelunga was shown in 1962 as an open roadster with aluminum coachwork somewhat reminiscent of a Porsche 550 Spyder. The next three cars, built by Fissore and also rendered in alloy, were coupes; their styling was very similar to the final production version. By the time the car was ready for production in 1965, Ghia was engaged to construct the bodywork, in fiberglass.

Perhaps the most interesting aspect of the Vallelunga is its central "spine" chassis. A large box section runs along the central tunnel of the car; on each end is a tubular structure to which the suspension is mounted. The engine and transaxle are employed as stressed members in the mounting of the rear suspension, standard race car design practice at the time. The benefits are light weight and exceptional torsional rigidity. Mr. DeTomaso was one of the pioneers of this chassis philosophy, and a similar layout lives on in the current Guara model.

For power the Vallelunga relied upon the race-tested yet simple Ford Kent 1500 cc OHV four cylinder engine, tuned to an output of approximately 100 horsepower and running twin side-draft Weber carburetors. Some of the cars were fitted with 1600 cc units. A Hewland 4-speed transaxle carries power to the independent rear suspension. The front suspension is also fully independent, and the Vallelunga features 4-wheel disk brakes. The beautiful magnesium alloy wheels were specifically cast for DeTomaso by Campagnolo.

Interior accommodations are race-inspired and simple, including the gated shifter and a full compliment of instruments. The Vallelunga is 12 feet 7 inches long, rides on a 90-inch wheelbase and weighs about 1600 pounds. Approximately 50 production Vallelungas were constructed, plus prototypes. The original roadster-prototype is owned by DeTomaso Modena, and is currently undergoing restoration.

Today the Vallelunga is often acknowledged as a modern design masterpiece. Traces of its shape can clearly be seen in other subsequently produced exotic sports cars. Other than current models, it is the rarest production DeTomaso, and the company’s genesis as a constructor of high performance automobiles.