Ferrari then founded Auto Avio Costruzioni (AAC) in Modena to manufacture aircraft parts and machine tools for the Italian government.

The company established business partnerships with other Italian firms, including Compagnia Nazionale Aeronautica and Piaggio.

[2] In December 1939, AAC was commissioned by Lotario Rangoni [it] to build and prepare two racing cars for him and Alberto Ascari to drive in the 1940 Mille Miglia.

[3] The 815 was designed and developed by ex-Alfa Romeo engineers Alberto Massimino and Vittorio Bellentani, advised by test driver Enrico Nardi.

[1][5] In concept, it was two 508C engines placed end to end, but it used a specially designed aluminium block built by Fonderia Calzoni in Bologna for integrity and light weight and a five-bearing crankshaft and a camshaft designed and built by AAC to get the traditional straight-8 timing and balance.

[4]: 23  The engine was high-tech for the time, with a single camshaft in block, two valves per cylinder, and a semi-dry sump lubrication system.

[4]: 35–36 Two 815s, numbers 020 and 021, were completed and entered in the 1940 Brescia Grand Prix, which ran nine laps of a 103 miles (166 km) street circuit.

[4]: 72–73  After leading the 1500 cc class in the first lap, Ascari's car developed a broken rocker arm and retired.

After locating the car and confirming its identity with Enzo Ferrari, he returned to collect it only to find it had been crushed during his absence, irreversibly destroying it.