I am an old car newbie and I need some guidance on troubleshooting an issue with a 1951 Chrysler Flathead 6. I was driving the car at low speed (less than 20 mph) when it shut off on me and would not start back up. It turns over, but will not start. I checked for spark, no spark at the plugs, and traced the issue back to the distributor. I first replaced the points, rotor, etc., still no spark. I realized the rotor was not turning and proceeded to pull the distributor and replace it with a tested NOS distributor, still no spark and rotor was still not turning. I did some research and thought that it might be a broken timing chain. I dug into the engine, removed the chain cover and the chain and gears/sprockets are in great shape. I cranked the engine over using the keys and the cam and crank sprockets turn, I seem to be getting compression on the cylinders, and there are no odd sounds when the engine turns. What's my issue?