Ferrari faced 1964 by focusing on increasing the displacement of its Sports cars, with a 3.3-liter (275P) and a 4-liter (330P), which was the Testa Rossa version of the 400SA, already tested in 1962 on the 4-liter GTO, on the 330 TRI LM, on the 330 LMB berlinettas in '63 and on a P in Reims and Silverstone. Three new chassis (0818, 0820 and 0822) were built with the new P-64 specifications, being fitted with either 3.3 and 4 liter engines, as needed race by race. A fourth chassis, 0824, would be fielded only in 1965. The 1963-specs cars were also converted to the new engines: chassis 0810, 0814 and 0816. The P-64s were also used by private teams, such as NART, Mecom Racing and the Maranello Concessionaires.