This model was also known as the P3/4, and was used by Ferrari’s privateer customer teams: NART, Scuderia Filippinetti, Ecurie Francorchamps and Maranello Concessionaires. The cars were basically P3 prototypes from the 1966 season but with the P4’s bodywork, suspension and alloy wheels. The two-valve per cylinder 4-litre V12 engine was also carried over from the previous year, but with Weber carburettors in place of the injection system.