For 1963, the French Maserati importer decided to develop the 151 that had debuted the previous year. The 151/2 was equipped with a new 8-cylinder engine derived from the series 5000 (4941.11cc) fueled by injection and power of 430 horsepower. The weight of the car had been reduced from 895 to 860kg. The 151/2 was not particularly competitive and in the main race of the season, the 24 Hours of Le Mans, Simon and Casner had to retire due to transmission failure.