You have ignition. You have cranking. Are you positive you have fuel? If you have fuel, it comes down to timing. Disconnect the vacuum advance, plug the hose on the vacuum side, and hook up your timing light. Check against your timing mark and see if it shows the same as before.
One that is not too uncommon is the fuel pump eccentric. If the bolt comes loose in the fuel pump eccentric, on the nose of the cam, the fuel pump will no longer pump. If the bolt comes out too far the timing gear will come off too. So check your fuel pump output; you can disconnect the fuel line from the carb and install a piece of fuel line routed safely away from the fan and ignition sources. Place the hose in a weighted container and have a helper crank the engine. If you get steady pulses of fuel in the jar, then your eccentric should be okay.
You can also often get a sense of what's going on inside the cylinders if you pull a few plugs. Are they wet and oily, wet and gassy, dry and looking new, dry and speckled, smashed electrodes, cracked porcelain?
Vikki 1969 Goldenrod Yellow / black 400 convertible numbers matching
