They never hit the market, but the pilot program went on for several years. The craziest part–even crazier than putting a turbine engine in a sedan–is that they were multi-fuel cars. They could run on anything that burned–gas, alcohol, vegetable oil–it’s just that in the 60s, no one was terribly impressed by that feature. But there are still a few in museums and one in Jay Leno’s garage.