Most of us carry a ballast resistor in the glove box. Don't scrap something out of frustration - it's old and it's going to have issues. We'll help you get back on the road. Where is the spark missing. Check the plug wires first, then the coil wire. If not at the coil wire, check to be sure you have power at the coil. Simple test. If so, you will need to move to the points that I am sure you still have. Take the cap off and see if they look burned up and be sure they are opening and closing. They are the old school hall effect switch that lets the coil fire. They fail quite often and are a cheap fix. Basically you need to backtrack the spark to find where it is lost. I'm sure others will weigh in with better suggestions than I have. We will see you back on the road!