Classification of this car is tough, since it could've been a nice American Graffiti '55 Chevy tribute car. Since it was initially offered for sale as the "verified" original Two-Lane Blacktop and American Graffiti movie car, it's listed here as a FAKE.
Above is a scan of the ebay auction wherein the seller makes all sorts of false claims about the car.
Above is a newspaper article that the owner proudly displayed with the car to document its authenticity as the American Graffiti '55. Too bad he didn't take a look at the bottom of the movie poster he was kneeling beside to see that Universal Studios released American Graffiti before he also proudly displayed his studio documentation from Paramount Studios, below.
Compare some of the details on the car with this old car magazine article from when Jim Zakias raced it and you'll see the car's true heritage. The seller could've sold the car for a lot more as a gasser with history than a fake American Graffiti '55.