I have a 64 as well. I made a search for a fuse block to replace mine when I re-wired my harness. When I called American Autowire I was informed that if they sold the actual fusebox then why would they be in business. Can't really argue that. They did however sell me a couple of generic fuseboxes that I used instead. See attached (if I linked it correctly).
http://s307.photobucket.com/albums/nn291/Rusty_1964/Body/?action=view&current=P1010495.jpg