'76 Dart Sport

A31 is suppose to be the Dart Lite fender code if the tag is still there. Put a magnet to the underside of the trunk and hood bracing. Hood would also be crimped to the aluminum underside bracing as well if it's a Dart Lite. The inside bumper reinforcements would be aluminum too. (The part between the bumper itself and the "shock absorber" bumper brackets.) Dart Lite would have been a 4-speed with overdrive or auto. No 3-speed sticks.

It could be a Dart Lite with the Spirit of '76 option.