you can’t, but you can check a few things.....it should have a “31” under the “ab” on the fender tag, it should have the .870 diameter torsion bars, it should have a sway bar in the front, it should have an extra leaf in the passenger leaf spring, it should have 14x5.5” wheels, it should have a crescent moon shaped cutout in the fold down panel between the trunk and the rear package area, on the trunk side of the panel, it should have a rectangular shaped cutout for the exhaust tip on the drivers side of the rear valance. It should also have all of the correct dress up package components on the motor, which should be a 273, and stamped with an “A” on the front of the block, just under the drivers side cylinder head, and the smaller 550 CFM Carter Carb with the 4 11/16” inch throat where the air cleaner sits. And of course some Formula S emblems. If it has a tach, that is an option usually chosen for the Formula S cars, although not standard equipment, and if it’s a 4 speed should have either a SG 7 1/4” rear, which would be standard equipment, or the optional 8 3/4”. That’s about all I can think of that would convince me.
