The 1959 Fiat 600 in question is currently in the hands of Ken Smith, who maintains a website on its history. For years, the car sat a junked state near the Talladega Museum before making headlines when it was discovered in 2007. "We didn't know what it was at first," he told AutoblogGreen, but bought it anyway and discovered that it had a fuel-saving past, running in the Wood River Mileage Marathons. Those events ended in the late 1970s, but with the Eco-marathons now back in the US, Smith thought it made sense to display the car. He also showed the car at the 2012 event in Houston.
"They'd crank it, run and then kill the engine and coast. Same thing they're doing here. They just did it with real cars back then."
The Fiat 600 ran at least three times in the Mileage Marathons, Smith said. It managed 173 mpg in 1967, 244 in 1968 and 304 in 1973. The car looks like a normal Fiat 600, but there were serious changes made inside.
"Basically, what they did was everything that ran off the pully at the bottom, they took off," he said. "The alternator is gone, the water pump is gone, the radiator is gone. There's no fan. They used electric pumps to circulate the water, and they used a small heater core as a small radiator for the air to come through, and the air would pick up the heat and help cool the water. But they didn't run the engine that long. They'd crank it, run and then kill the engine and coast. Same thing they're doing here. They just did it with real cars back then."
You can read more about this year's Shell Eco-marathon here and here.