The 1952 roadster-bodied C-4R and C-4RK coupe were smaller and lighter than the earlier cars and, thanks to more engine development, were now putting out 325 horsepower. Once again, a three-car, six-driver team took up the challenge at Le Mans. George Rice was paired with John Fitch in one of the roadsters, Phil Walters and Indy veteran Duane Carter would drive the coupe, and Briggs and Bill Spears handled the other open car.

Walters took the coupe into the lead on the first lap, setting the team's top speed mark for the race at 105.6 mph. Having settled into third place after forty laps, Walters handed the car over to Carter, who promptly stuffed it into the sandbank at Mulsanne. Carter finally extricated the car after almost two hours of digging, but just before midnight, the coupe joined the Fitch/Rice roadster in retirement, caused in both instances by valve trouble due to over-revving during downshifts. The problem of insufficent brakes had struck again.

Briggs, who was a stickler for going easily on the equipment, had been driving throughout the day and into the night. By 3am he was in tenth place and by 7 in the morning had reached seventh. He finished in fourth, having driven an incredible twenty of the twenty-four hours.

It was more than twenty years before Briggs reluctantly explained his reason for staying in the car for so long: during a visit to the medical tent at Road America earlier that season, he had overheard a doctor tell his Le Mans co-driver Bill Spears, "You have a vision problem and must never drive without glasses."

Cunningham explained further, "As I drove along at Le Mans that night all I could think of was what the doctor at Road America had said, and all those overtaking problems at Le Mans and the fog that probably would come in again in the morning. So I just stayed with it until late Sunday."

The C-4R roadsters and coupe had shown excellent potential and would benefit from ongoing development, twice returning to the Sarthe and practically owning road racing in the United States for the next two years.