 Complete the following phrase:  Between 1954 and 1956 Salvadori drove a Maserati 250F in Formula One for Syd Greenes Gilby Engineering team, taking a numerous good results in predomitly non-championship F1 races, with one entry for Officine Alfieri Maserati in the Großer Preis der Schweiz where he did not start and the car was driven by Sergio Mantovani. It was in the 