Some where on this site there is a 10 minute (or so) video of cars going down Sunset Blvd. in the late 30's. Only one car, a Rolls early in the video had white walls.
Do you belong to the ACD club ? There is a list of owners that have 31 & 32 cars. All the parts are had by the owners. Start at the top and call each of them. You will find what you need.