Originally Posted by Salamandrine

No, not backwards. That's correct. They are really way too long, though it wasn't that unusual at the time. No wonder they won't stop a feather. I suggest trying to find some shorter straddle cables. Mechanical advantage is very low when they are that long. A little tricky to change those since they are the fixed at both ends type. I'd suggest the OP get some dia compe or similar barrel stops and make custom straddle cables. Old ROT was to make a 90º angle between straddle cable and imaginary line from brake pivot to where the straddle cable connects.

Also, get some Kool stop brake pads. The brakes will work then. I wouldn't do anything else to that bike except get some decent tires. Modern tires are better. Knobbies suck unless you ride in mud or sand all the time.

Cool bike BTW. Really doesn't need anything other than brake adjustement, pads and tires, IMO.