Solving a Misfire

Could be compression, burned valve, misadjusted valve, valve sticking/ bent

Could be ignition--even a bad plug.

Could be something AKA leak causing "lean" in one cylinder. Pay particular attention to "how even" plugs look

Here is what you do

Pull the plug and coil wires and check them for continuity with an ohmeter. Try new plugs. Plugs CAN go bad with no apparrent external "look"

Beg borrow or steal a compression gauge. Google "leak down tester" you can actually make one if you are handy, and use your compression gauge for "parts" for the leak down tester. Lacking that, buy or make an air fitting.......or use the parts of your compression gauge........so you can inject air into each cylinder and listen at exhaust, carburetor, etc for leaks

Next do a power/ load test. This will show what is weak and maybe if there's an ignition problem You really need a tach (tach/ dwell meter) and you can find these used dirt cheap

"Rig" a small probe, screwdriver, with a ground wire. Pull the plug wires up a bit off the distributor so they are loose and so the boots are up off the distributor towers Leave the wires in enough they will still work OK. Another thing you could do here is insert small brads/ finishing nails, pieces of wire/ paper clips down alongside each wire. Now go around the cap with your probe and short each tower. Listen for the drop in RPM it should be even with each cylinder. Also watch the spark as you approach and ground out each tower. The spark should be "hot" and even at each cylinder.