[5] The 6C 34 was equipped with an in-line six-cylinder engine that was 30 hp more powerful, and 13 kg lighter, compared to the eight-cylinder installed on the 8CM.

[6] Only five days after the completion of the engine tests on the dyno, the 6C 34 made its racing debut at the 1934 Italian Grand Prix where, due to brake problems, the car did not perform well.

At the following Grand Prix, on the Masaryk Circuit, the 6C 34 driven by Tazio Nuvolari finished third, surpassed by the elusive Mercedes-Benz and Auto Union, but ahead of the Alfa Romeo P3.

In 1935 adjustments were made to the chassis to stiffen it, and new suspensions were tested, which were now independent wheels and with the Parisi system.

The experience of the 6C 34 in racing ended as a semi-official car for the Scuderia Subalpina, driven by Achille Varzi, Pietro Ghersi, and Eugenio Siena, achieving important placings but no victory.