Does a Dart windshield fit a Valiant?

I disagree with that. Oh wait, the "post car" may make the difference....

I had a 69 Valiant 4 door and had the windshield removed to have it installed in my 68 Barracuda Fastback. The window guy said that they were not interchangeable. Luckily, he removed the Valiant window from the parts car first and we set it over the Barracuda window, and it was about 1" taller, and the Barracuda was my daily driver (It would have sucked to have to pay him to remove and install the same windshield)....

Post car is the difference. The Barracuda windshield interchanges with the hardtops.