These are Yokohama Truck tires from Diamond Back; 750 R16. The whitewall band is 3.75" and I had the beauty rings put on at extra cost. Unfortunately I don't have any close ups that show this feature, but I think it was money well spent.
It is often wrongly assumed that cars of the 30's and 40's had these huge wide whitewalls, but in fact, these are often incorrect, depending on the year. Also, many large series Cadillac's of 30's and 40's were shipped with black walls. Sometimes the cars had the chrome work painted rather than plated.... this was apparently very common in the Philadelphia area where the wealthy were extremely conservative. Sometimes at car shows you may overhear someone say "how Philadelphia that car looks" and they are generally referring to a large luxury car that has black tires and other features purposely toned down.
Whit