I have had a few beaters in my day with some of the same problems. The last one was an 82 honda civic... what a piece!! Anyway it had the same problem and it turned out to be a bad ground. Check the simple things first. All it's lights and guages would come on and as soon as I would turn on the key it would die and every thing would shut off.
69 Camaro RS, 355ci mild cam, Preformer rpm intake, edelbrock 600 carb, 350 turbo w/ shift kit 2500 stall, 10 bolt 2.73 any more questions ask