Defending winner with the 375, in early of 1955 Scuderia Ferrari traded its V12 engine for an inline 6-cylinder 4.4-liter (based on a 4-cylinder), developed by the engineer Lampredi, to power the 121 LM. Of the three cars entered at Le Mans under the official banner, two were true 121 LMs, and the third - the 0546 LM chassis in question - was a 118 LM transformed into 121 LM, just like the 0484 LM chassis.

Though the Ferrari 121 LM was much faster than its rivals, it was not as reliable at the 23rd edition of the 24 Hours of Le Mans, tragically overshadowed by the accident for the Mercedes driven by Pierre Levegh. Though Eugenio Castellotti's #4 Ferrari 121 led the charge with the #19 Mercedes of Juan Manuel Fangio and the #6 Jaguar driven by Mike Hawthorn at the beginning of the race, causing the lap record to be beaten 10 times, engine troubles soon plagued the Italian's car and he was forced to retire during the fifth hour, followed shortly thereafter by the #3 sister car of Phil Hill and Umberto Maglioli.

The sole left in the race, the #5 car driven by Maurice Trintignant (winner in 1954) and Harry Schell was forced to retire during the 10th hour after the engine failed, so at mid-race none of the three official Ferraris remained. The 0546 LM chassis had not fared better at the Mille Miglia a few weeks earlier when Paolo Marzotto (Eugenio Castellotti's teammate at the 24 Hours of Le Mans) saw his efforts dashed when a flat tire prompted an accident just as another 121 LM reached the third step on the podium.

In the wake of the 121 LM's disastrous results, Ferrari - who in any case would not have been permitted to enter 121 LMs at Le Mans in 1956 as prototypes were subsequently limited to 2.5-liters in response to the previous year's catastrophic accident (models produced in 50 units or more could exceed that capacity, like the Jaguar Type Ds) - sold the four cars in the U.S. at the end of that year. They achieved considerable success in shorter races less demanding on the fragile engine. It was during one of those races, in the streets of Pebble Beach in California, that after losing control of the 0546 LM chassis, Ernie McAfee hit a pine tree along the road and died instantly. The Del Monte Trophy did not survive the tragedy, unlike the Ferrari 121 LM whose owner, CEO of Superior Oil Company William Doheny, had repaired.

Thereafter, the car changed hands twice in between a few rare appearances at vintage car events before leaving the public eye in 1999 after the Ferrari North America Historic Challenge of Lime Rock Park, and reappearing in a twist of fate at Pebble Beach (in the county of Monterey) this week. RM Sothebys estimates the car will sell for 6.5 to 7.5 million dollars (between 5.5 and 6.4 million euros).

Photo (copyright Archives ACO): The #5 Ferrari 121 LM in the darkness of the 24 Hours of Le Mans in 1955.