The limit on the number of starters was further reduced to 350 and the organizers again took steps to try to combat the unsportsmanlike tactics by which some competitors sought to negate the procedure of drawing lots for departure times/numbers. These rather belated actions did not have the desired effect and, in the event, only 298 cars left the starting ramp in the Viale Venezia.
Even though the Mille Miglia continued to count for what was now called the World Sports Car Championship, reserved for Sports/racing cars, only Ferrari and Maserati entered works teams. Maserati had two 4.5 litre V8s for Stirling Moss and Jean Behra, a brand new 12 cylinder 3500cc for Hans Hermann and a six cylinder for the Italian Giorgio Scarlatti. Ferrari entered four Sports/Racing cars driven by Piero Taruffi, Peter Collins, Wolfgang von Trips and Alfonso de Portago the wealthy son of a Spanish potentate, who was a polo player as well as an Olympic bobsledder and his close friend Englishman Edmund Nelson. Britain was represented by a single semi-works Jaguar D Type entered by the Ecurie Ecosse for Ron Flockhart. One of the more unusual entrants was a Caballo de Hiero, constructed in the Untied States with a powerful six litre plus Chrysler engine mounted on a rudimentary single seat chassis, designed for use on oval circuits such as Indianapolis.
Soon after the race started Maserati’s hopes evaporated. Before this, Behra had not even made it to the starting line because of an accident during pre-race tests on an open road. Moss was forced to retire shortly after the start having rather dangerously snapped a brake pedal and Hermann did not get as far as the Ravenna checkpoint. Victory then went to Taruffi and Ferrari, but in Guidizzola, less than forty kilometres from the finishing line, Alfonso de Portago’s front tyre exploded. The car now out of control, hit a telephone pole, jumped over a brook, hitting a few spectators in the process. Then the car bounced back on the road, hitting more spectators, slid over the road, spinning, and ended up, wheels down, in a brook at the other side of the road. Besides De Portago and his navigator Edmund Nelson, ten spectators – among them five children who were in the first group of spectators – lost their lives. Twenty more were injured. Three days later the Italian Government had enough and decreed the end of the Mille Miglia and of all motor racing on Italian public roads.