Unless you are a large person I don't see a need for a 'D' wheel in a early car.

I believed they were originally made for small race cars (as in non street as in formula v, Indy car) bodied cars where notching of the wheel helped with interference issues.

I don't think race cars in your year body style ever had them.

Allen Here's a novel idea, let's not throw a bunch of parts at the car hoping it will fix the problem and instead spend a little time diagnosing it first. Life was a little easier when I was just a wrench.