32 total 250 LM chassis were built from 1963 to 1965, with all but the first chassis (s/n 5149, the Paris Auto Show car with a 250 P engine) powered by 3.3-litre 320 bhp (238 kW) engines as used in the 275 P. According to Ferrari naming convention, the 3.3 litre cars should have been designated "275 LM", however Enzo Ferrari insisted that the name remain 250 LM in order to facilitate the homologation process. The 250 LM shared fully independent double wishbone suspension, rack and pinion steering, four wheel disc brakes and 5-speed transaxle with the 250 P, however the tubular space frame chassis was significantly strengthened with the roof structure, additional cross-bracing and heavier gauge tubing. The interior was trimmed out as a nod to the ostensible production status of the car, but ultimately it was little different from a prototype racer.