I am considering the same thing for my 63. I have been communicating with Colorado custom wheels to make replicas of the stock hub cap in a wheel. He says either size works. He can send you a template to measure your car to know for sure. I plan to still do stock looking white walls so I’m leaning towards 20’s. I’m curious what you select and how it looks.

Hey Mike, hit me up. I think the place I’m going to use for my wheels might be able to help you out.