Centerline front runners on my 73 scamp????
years ago my BIL had a 73 Dart -- he put a set of Keystone Klassics on it and they never set correctly, wobbled like crazy - it was a front drum car. It turned out he needed a set of spacers because the drums have a weight on their face that interfered with the mounting surface of the wheel - that's my guess here.
Easy to see weight here:
it sticks out just enough to cause a wheel mounting issue with some wheels