Foreshadowing his later relationship with Jaguar, Cunningham entered the
1955 Sebring 12 Hours with a factory-supported D-Type driven
by Phil Walters and Mike Hawthorn, finishing first overall
after a scoring debacle that had Carroll Shelby and Phil Hill
briefly declared the winners.

Also entered was the new (and yet unpainted) C-6R, driven by Briggs
and Benett. Lacking in development, the car retired on the
fifty-fifth lap with transmission failure. The car would undergo
several improvements before Le Mans, including a headrest/tailfin
similar to that sported by the D-Type Jaguars, and a smaller
grille opening to aid the car’s aerodynamics. Yet its biggest
weakness remained: the Meyer-Drake Offenhauser engine, which
was well suited to its Indianapolis roots, could never be
modified satisfactorily for the ever-changing loads applied
by road racing. Converting it to run on gasoline reduced its
power output to the extent that the car was slower than the
previous year’s C-4R by almost eight miles per hour.

Yet it was the gearbox which bore the brunt of the Offy’s shortcomings,
losing the lower gears early in the race. Driving to compensate
for the lack of acceleration proved too much for the engine
and the car was retired after eighteen hours with a burned
piston.

The 1955 race was also the occasion of the worst accident in racing
history. Pierre Levegh, driving a Mercedes 300SLR at over
150mph, swerved to avoid Lance Macklin’s Austin-Healey as
the two passed a slowing Mike Hawthorn in front of the pits.
The Mercedes glanced off the earthen bank across from the
pits, deflected off the back of the Healey, and was launched
into the crowd, breaking up as it went. Levegh was killed
instantly; upwards of eighty spectators also perished. It
was a shocking event, one which almost put an end to racing
in Europe.

“I don’t believe that the accident had anything to do with my
decision to stop building cars,” Briggs said years later,
“but I don’t think that Phil Walters ever raced again.
And I can’t say that I blame him.”