The P3 was a monoposto Grand Prix based on the 8C 2300 mechanics. The 8C name was given to a car bearing the 8-cylinder engine developed by Vittorio Jano. Jano had already developed the 1924 Alfa Romeo P2 to replace the over complicated and unsuccessful P1. The P3 continued Jano's development and used the 8C 2 x 4-cylinder blocks in line, with components from the 6C 1750 for a 2,645cc P3 racing car (Tipo A). The P3 was the first ever monoposto racer, but in 1934 body had to be made wider to comply with new regulations so the engine was enlarged to 2,905cc for the Tipo B. The engine had twin super-chargers, and a special model was made for the 1935 German Grand Prix with a 3,165cc engine; it won on the final lap after the leading Mercedes failed.