for the 1964 season, ferrari developed the 275 p and 330 p. these were improved versions of the 250 p with larger displacement engines and slightly modified bodywork. the tubular space-frame chassis and most other components remained the same as in the 250 p. the 275 p used a bored-out 3.3l version of the 250 testa rossa-type engine originally utilized by the 250 p. the 330 p used a different design, a 4.0l colombo-designed v12 based on engines used in the 400 superamerica road cars. the 330 p developed more power than the 275 p (370 bhp vs 320 bhp) but weighed more (785 kg vs 755 kg). some drivers preferred the extra power of the 330 p while others appreciated the more nimble feel of the 275 p and the two models were raced concurrently. production of these types included three brand new chassis and conversions of all four 250 p chassis. it is not possible to clearly determine the number of chassis produced with each engine type as 275 and 330 engines were swapped as needed between cars.