If I recall from the days of points, I always replaced the condenser when I changed points. That way you are sure of a good condenser that will suck that spark up as the points open so they dont burn up the contacts. You may want to view the whole system when it is running while in a dark room, that will show you any escaping fire in the system also. I would replace the distributor cap if it is really old as they can develop minute cracks that moisture seaps in and you only have a problem with starting, Once it starts and runs a while the moisture dries out from the electrical current running the minute crack and it runs ok from then on. If it cranks up well when Hot that could be your problem or just a weak coil. I can remember replacing the coil once because of weak fire and still had a problem. Pulled my hair out looking for something else till I finally took the coil back and they tested it. The new one was bad also. Not much on those old 8n's to be the culprit-wires, plugs, distributor cap, points, condenser, coil and rotor . If the battery is hot, it should have good fire if all the above are verified good.