Vacuum Advance unit for 8ba distrinutor

[GB SISSON]

I have done a search here but cannot find a source for a replacement part for the vacuum advance on my 7RA Load-a-Matic distributor. To me it would seem that a 70 year old NOS part might not be the best choice. I tend to buy ignition parts from napa as we have one where I live and since the company moves a lot of parts I feel their inventory would be current. Our napa store has recently changed hands and the new generation is less familiar with how to round up this stuff from the past so does anyone have a napa part number? A Ford part number would also be beneficial for a search. I have not found them on ebay or amazon.Happy to buy from one of our vendors too if someone could direct me. . Thanks in advance (no pun intended) GB