The very first Testadoro, closely derived from the production Fiat 500 "Topolino," from which it retains the original ladder-frame chassis. The engine was increased to 660cc and fitted with the famous "Testadoro" cylinder head with overhead valves and a hemispherical combustion chamber. The highly articulated body design is attributed by some sources to Testadoro's "communications manager," the painter and illustrator Carlo Biscaretti di Ruffia.

The second car produced by Testadoro addressed the stylistic "heaviness" of the "Sport" while simultaneously introducing significant improvements to the production chassis, which was described as "modified" in publications of the time. The "Drin Drin" (the name comes from the nickname of Giorgio Giusti's wife, Andreina) marked the beginning of the collaboration between Testadoro and the Zagato coachbuilders.

For the 1948 racing season, Testadoro fielded its first car developed and produced entirely in-house, while simultaneously expanding its collaborations with component manufacturers. Elio Zagato, who had since become an official Testadoro driver, introduced his friend Gilberto Colombo to Giusti; Colombo was the undisputed leader in the development of tubular chassis made from special aeronautical steel. The Marinella (named after Giusti's first daughter) therefore featured a Gilco tubular chassis and a "Siluro" body designed and built by Zagato.

This version of the Marinella was better suited for endurance racing and was also built by Zagato; Elio Zagato himself won the 750 class at the 9th Giro di Sicilia in 1949, together with another official Testadoro driver, Ugo Puma. The car was later equipped with a hard top for a quick conversion into a coupé.

The Daniela (named after Giusti's second daughter) represents the pinnacle of Testadoro's historical production. Inspired by the Alfa Romeo 158 "Alfetta," the dominant Grand Prix car of the era, it features a Gilco "Isorigid" chassis with torsion bar suspension, an engine developed entirely in-house, and "Siluro" bodywork signed by Zagato. The Daniela dominated its class at the 1949 "Gran Premio Vetturette" in Monza, with five cars at the start and a victory by Mejnardi. The most famous Daniela, with a modified front end, was imported to the United States by Tony Pompeo, who raced it until 1958, when he sold it to George E. Waltman, who raced it for years on East Coast circuits.

After relaunching the Testadoro brand, Dario Pasqualini came across a project for the 1100 Sport class that had never been built. The tubular trellis frame and the bodywork, designed for maximum aerodynamics and lightness, are typical expressions of Testadoro production. Although there is no record of production plans for this model in official historiography, the design was so compelling that it deserved a second chance: production of a unique model based on the original blueprints began in 2019 and was completed in 2021, exactly 70 years after the original drawings were made.