I've got a 1965 Ford Falcon from my father, it was his first car and now it's my turn to take care for it.
Some parts need to be replaced or rebuilt and it's a great challenge to figure out how to do it or find spare parts, specially in my country.
When I was rebuilding the electrical system the problem was to find a replacement, because I could't find it I had to figure out how to rebuild it and this is how I did.
*** Updated on June '16 ***
This guide can be used for a lot of cars from the 60's up to the 80's but I'll try to write specifically about the ford falcon/mustang/cougar ones.
Users have reported succesful applications on:
64 to 68 ford mustang, falcon, galaxie, fairlane.
68-73 pick up truck and mavericks.
Dodge charger, super bee and most Mopar B body cars
84 Mazda B2000
Your fuse box must look like this: