The car in the pic is described as a bel air, get all the prices for all the cars, you know it's a 4dr sedan, there should be a listing for Bel Air, 210 and the 150, then look at the actual car and see if it's a bel air or not, bel air markings should be on it but mey have been removed, If I remember right the 150 and 210's are not marked at all and only the trim tag can tell them apart, someone could trick you into thinking a 150 or 210 is a bel air if it had no bel air markings, the Bel air is of course more valuble in a 4dr or not. On my car, maby not on a tri 5, the trim tag is on the right side of the cowl, that's where I'd look for it, have to have the hood up though. There are plenty of sites with # to tell tri 5's ( '55, '56 and '57 Chevys ) apart. Check the # and decode the whole trim tag.