Inspired by the F1 program, and the ALTA four-cylinder engine, Ferrari built three large-displacement, 4-cylinder prototypes known as the 860 Monza. These were used in the 1956 season as factory competition cars alongside the V12 290 MM.
The first two Monzas appeared at the 1956 Twelve Hours of Sebring and were entered for Scuderia Ferrari. At this season opener, they had great success: the car of Eugenio Castellotti and Juan Fangio placed first overall with the second Monza of Luigi Musso and Harry Schell taking second place.
The Sebring winning 860 Monza, chassis 0604M remained in the United States for John von Neumann to use. 0602M and a newly built 0628 continued under the Scuderia Ferrari banner as factory prototypes for the World Championship.
At the 1956 Mille Miglia, the two factory 860 Monzas were entered, one for driver Peter Collins and photographer Louis Klemantaski who snapped famous color photos of the event from the passenger seat. They finished second overall in car #551 while Luigi Musso was 22 minutes behind in #556. Both were beaten by the Ferrari 290MM of Eugenio Castellotti who won the event overall.
For the rest of the season, 0602M and 0628 were used by the factory to clinch the World Sports Car Championship. Eugenio Castelotti won the GP of Rouen outright.