No idea. The 65 fenders will actually bolt to the inner fenders of the 63/64 but nothing else (valence, grille, hood ,etc) will. Now taking that same 63/64 Dart as the base, if you swap the complete front clip of the donor 65, everything fits and lines up as it should. With all that work you’ll have visually a 65 Dart. You can do a complete front clip swap from a Dart to a Plymouth. Doug Dutra of slant 6 fame did that swap. He had a early Barracuda and swapped a complete 63 or 64 Dart front clip to it. There’s pics floating around the net