In view of the 1923 season and encouraged by the success of the RL, Giuseppe Merosi launched the project for a new GP car, completely new and based on the sporting regulations in force since 1922, which limited the maximum displacement to 2 liters, the minimum weight to 650kg and also the length of the tail. Thus was born the GPR (baptized by all P1) with a 1990cc 6-cylinder in-line engine and 95 horsepower at 5500 rpm. The debut was in Monza for the 1923 European GP but the team withdrew due to the fatal accident in Sivocci which occurred in practice. One of the GPRs was later taken up by Vittorio Jano to experiment with some solutions to be used on the P2. Three exemplars of GPR were built.