Powered by ...a steam engine.
A one-off experiment by General Motors Research Laboratories, with assistance from Bill Besler (an engineer who, thirty years earlier, and built and flown a steam powered aircraft). The engine was a dual cycle V4 (half of a GM V8) with two high pressure and two low pressure cylinders driving a standard clutch and three speed gearbox. There was a recirculating steam system which recycled about half the water. Car could cruise at 65mph, getting about 16mpg. When the project was finished the car was given to Besler, who, years later, gave it to Harrah's museum. Some years later it was auctioned and is now owned by Tom Kimmel, an engineer and steam car collector; who hopes to get it running again (5000 miles on the odometer, all under steam power).