'64 Dart, '73 Scamp. What's the difference???

Looking for a starter for my '64 Dart 225/6 online. The '64 starter is unavailable. So, I punched in a random, later-model Mopar. The '73 Scamp. Bingo. They have THESE starters all over the place. I would assume that there wouldn't be any significant difference. But, before I go yanking out my starter and rolling to Napa, I'll toss out the question:

What's the difference????