If you plan on keeping the car for a while, do yourself a huge favor and buy an aftermarket fuse block/Wriring. Don't cheap out on a used one because if you have a problem, like a short and a fire, you'll never forgive yourself.
I used the E-Z 12 circuit system. I am not an electrical madman, just a hobbist. It was clear and simple. go with the new one.

RapRap
1940 Chevy Coupe