After WWI, Fiat resumed its production and started to improve its lineup.
After the 501 model, it introduced the upgraded 503.

Fiat was already on the verge of conquering the European car buyers. It was already the leading Italian carmaker and covered more than 50% of its home market. The 501 model was good, but Fiat knew that it could do better. It already developed new engines, new transmissions, and new braking systems and included all of these in the 503, launched in 1926.

Most of the cars from that era were built almost in the same way, with ladder-chassis underneath, solid axles, and custom bodyworks.
Fiat offered the 503 as an open-top with two doors, four-door vehicles, or a closed cabin, suitable for limousines and upmarket customers. The Torpedo-style featured a four-door construction with an open top. Its canvas-roof could have been folded behind the rear seats or completely removed and left behind in the garage.

The 503 interior was limited to bare essentials. Apart from the instrument panel, which was placed in the middle, there was a four-spoke steering wheel on the right with a lever on it to adjust the engine’s timing. For selected versions, the carmaker installed a second windshield for the rear passengers.

Under the hood, Fiat installed a 1.5-liter engine, which provided only 27 hp. But it was enough for those times. Some of the updates included on the car were the drum-brakes in all corners and a 4-speed manual gearbox. Most of the cars from that era featured only 3-speed gearboxes.