Looking to improve the performance of their front line fighters, in 1942 the Regia Aeronautica decided to change to the new 1,475 hp (1,100 kW) DB 605 engine, license produced in Italy as the Fiat RA.1050 Tifone. Fighter manufacturers were invited to enter versions of their designs with this engine as the "5 series" and were provided with imported 605's for prototype use. All of the designs used a 5 in the name, with the Macchi becoming the C.205 (instead of C.203).