After WWII, Fiat was in bad shape and dug into its former warehouses to find older chassis to built new cars upon them, and the 1100 model was its best bet.
But the story didn’t end there, with the Italian carmaker rely on an armada of pre-war designed sedans. The carmaker had enough enthusiasts in its team that wished to find their glory days on the tracks. It was also an excellent advertising way, and Fiat’s management agreed to use its resources to develop a sport version named 1100 S.

Dante Giacosa was Fiat’s lead engineer and supervised the project. Some sources said that Giuseppe Cogno designed the bodywork based on the Fiat 508 C MM made in 1938 for the Mille Miglia race and built it on the Carozzeria Speciali office. The carmaker used fiberglass to build the body with flared wheel-arches and round headlights. They couldn’t make a rounded windshield, so they used two glass panels and installed them slightly raked in a V-shape. The rounded and extended greenhouse ended behind the seats. It was not the best aerodynamic solution, but it saved some weight, which was far more important for the Mille Miglia race. In 1947 Fiat entered the race and placed four of its cars in the top-ten final result. It was a remarkable achievement for the Italian carmaker. Worth mentioning that a fifth Fiat 1100 (not an S-version) driven by Comirato Dumas took another spot in the top-ten list.

Under the hood, Fiat engineers used the same 1.1-liter engine from the rest of the 1100 B range but tuned to offer more power. They paired it to a four-speed manual gearbox.