After the experiments with the 151 of 1962 and the 151/2 of 1963, a much modified version was prepared for 1963, called 151/3. The 4941cc V8 engine was the same as the 151/2 (the 151 had the 4 liter V8 instead), but the chassis and body were different. The nose was lowered and the tail was higher with a horizontal rear window. Fielded in the 24 Hours of Le Mans, the 151/3 for Trintignant and Simon, the 151/2 had to retire due electrical issues.