cylinders 1 and 4 fire from the top coil and 2 and 3 from the bottom.
rules out a coil.
did you drill out and remove the brass plugs that cover the air fuel screws and clean that passage?
did you reset all shutters with a 4 channel manometer?
why check timing, its not adjustable.
its either where it supposed to be or broke.
no moving parts,other than a flywheel and the TPS really involved in timing once the engine is warmed up.
I would test leakdown then go fix the carb issue.
