The Nash Ambassador paces the field of 30 cars for the 31st running of the Indianapolis 500 on May 30, 1947, with American Motors CEO George Mason behind the wheel.
The Ambassador, powered by a 112-hp inline-six engine, was mostly a bone-stock 1947 four-door sedan, with a trunk.
Hemmings Classic Car called it "a handsome body style that was rapidly displacing the Slipstream fastback sedan in popularity."
The body was painted bright canary yellow, a one-off color not offered by the factory, with a black roof.
It was the only time Nash supplied the pace car for the race.
In addition to the yellow body and black roof, the Ambassador was noteworthy for another reason: It was a sedan doing what convertibles and coupes had often done.
Nash wasn't the first automaker to use a closed car as Indy pace car. Studebaker paced the 1940 race with the Champion two-door coupe. And the Ambassador wasn't the last closed car either -- several sport coupes have paced the Indy 500 since the 1970s, as well as numerous two-door models with a T-roof. And the Oldsmobile Aurora, a sleek sedan, served duties in 1997 and 2000.