Interchange Numbers

Having obtained most of the pertinent repair manual/parts numbers for my '56. It is now time to acquire a parts book which affords me interchange flexibility, well as much as a 50+ year old car will allow, and I was wondering what the members recommendations towards that end would be. Is a Hollander the best way to go? Will I find a book, or a combination of books, current to today's number's which can reach that far back via cross referencing? What is realistic? Thank you as always.