Tail light stay on

Being as the car and most of it's components are 50+ years old, there is no telling how many hands have been on it or, what all of those hands have done and/or changed. In my opinion, if the fuse block looks to far gone you may want to see if another can be found or yours cleaned up to the point everything is serviceable. The other option would be to use an aftermarket fuse block and harnesses.