A Few things to check.
I would start with the cap and rotor. Make the cap and rotor has no burnt terminals. If you have a meter you ohm the wires to check they are ok. Did you hear any noise coming from the engine (ticking etc.?) If the wires are good I would consider pulling the valve covers and making sure a rocker (s) did not back off. This happened to me once and killed 2 plugs.
The idle screw on the side of the carb should be set 1 1/2 turns out as a baseline and fuel press 5-7 lbs.