Opinions please

I have a 74 Duster. It has electronic ignition. It started running rough, almost like it was running on 7 cyl or something. Eventually it wouldn't even start anymore. Would just backfire through the carb and then finally it just quit. No power at all. No headlights, domelight, nothing when you turn the key. I figured it was the ign module box.. When I took the old one off there was a hole in it. I'm figuring problem solved. I install a new one. All power comes back. I turn the key, I get one click and all power is gone again. Could it be the starter is bad and drawing too many amps? I've replaced the starter relay as well. I would appreciate any advice. Thank you all in advance.