The Chrysler 300 “Letter Car” series, produced from 1955 through 1965, is significant for helping shape and popularize the muscle-car genre that remains a favorite of collectors and enthusiasts today.

A resounding success upon debut, both commercially and in competition, the 1955 C-300 delivered the looks and luxury of a Chrysler New Yorker with the performance of a racecar—literally.

The C-300 absolutely dominated NASCAR competition right out of the gate, with driver Tim Flock clinching the 1955 championship after an impressive 18 wins.

The C-300 would go on to become one of NASCAR’s winningest cars of all time, racking up 49 victories through the 1957 season—along with accusations that its drivers were somehow cheating, given the car’s unprecedented success.

But there was nothing untoward about the C-300.

Its success owed largely to the 300-brake-horsepower 331-cubic-inch Firepower V-8 engine with its pair of four-barrel carburetors and race-spec, high-lift camshaft.

A heavy-du...