Plymouthguy

(1940 Plymouth with 1966 Valiant Motor) I replaced my 60 amp alternator along with the 2 belts. When I hooked everything back up and tried to start the car it turned over once and then the electrical system went dark. Seemed as if I had my belts too tight and blew a fuse. Problem is, I don't know which fuse would cause an entire system shutdown. Need some help!

440roadrunner

No way possible for us to know that. A 12V, modern engine conversion in a 40 car? Are you kidding? We don't have a crystal ball, nor have any way in the world of knowing how that car might be wired.

You still have the original ammeter? Might be a problem there. I doubt the alternator is the cause of the trouble, unless it's defective, that is, a massive internal short, which "could" have caused fuses / fuse links to blow

If I were there, wherever "there" is, we'd have this found in short order.

I would disconnect the battery and put a lamp in series with the battery. This is to protect everything, especially wiring, in case of a short.. Use a large heavy lamp such as a turn signal or headlamp. If the lamp lights bright, you have a heavy load or short.

Now take a test lamp or multimeter and find out where there is / is not power.

ZombiePopper

Being a 40 it would've been a 6v system, wiring and components originally.
What has been replaced?

RacerHog

Check the grounds...
Also check the starter relay for power...