65 Dart 270 -- 273 - 4 speed

what's the fender tag say?

do you have a build sheet to corroborate the information?

none of the early cars came with duals from the factory, and there's no cut out on the valence so that may be your first set of clues. however, a lot can change in 60 years...
This is the fender tag -- Do not have the build sheet.

1 - 65 Dart - Vin Plate.jpg