Only two examples were produced (chassis numbers 0646 and 0656), and both were further converted into a larger displacement derivative, the 315 S, one before 12 Hours of Sebring, the second after the race.

[5] The new Jano V12 engine, codenamed Tipo 136, received a new configuration with twin overhead camshafts per cylinder bank.

The internal measurements of 73 by 69.5 mm (2.9 by 2.7 in) of bore and stroke, and the resulting total capacity of 3,490.61 cc (3.5 L; 213.0 cu in) remained the same as before.

[8] The first car s/n 0646, was driven by Eugenio Castellotti, Luigi Musso and Maurice Trintignant, and managed to qualify at a second place.

The engine was upgraded to 315 S specification for Sebring race by March, and the car was subsequently destroyed at the tragic 1957 Mille Miglia in the final 335 S guise.

Issues with an oil pressure had forced Peter Collins and Mike Hawthorn to retire after completing only two laps.

Masten Gregory with Lou Brero drove the car, entered by George Tilp, to a fourth overall and a third in class.