Back in the day I did tune ups with a dwell meter ,timing light and a vacuum guage. And you would be surprised how many tines I discovered a bad vacuum advance. Today I know where two timing lights are covered in dust . haven't seen my dwell meter in decades. The 283 in the 55 in my avatar has points . I adjust them by the adjust to stumble and back off a half turn. the timing I advance until it kicks back on the starter. then back off until it don't. I still used a vacuum guage to adjust the carb idle mix screws. my son Chris had a dirt bike. It wasn't firing. electronic ignition. He built up a lobe on the shaft with JB weld. screwed a set of chevy points to the side. and adjusted till it ran pretty good. The points where out in the open. He would get his leg too close and get a shock or 50 LOL. the cover wasn't deep enough after he installed the points. A neighbor who worked at the Tool Box Factory took the cover to work and got the machinist to machine out a aluminum spacer to fix it.