A few other parts I would check are valve guide clearances for excessive clearance,cylinder head straightness with
a straight edge and feeler gauges ,bent push rods,loose rocker posts,sometimes the valve seats come loose.
I have heard of a few wiring faults that can cause intermittent running problems .The wire that goes to the fuel bowl solenoid can short out,
I would check the easiest problems first like the fuel bowl solenoid. You can Test the Fuel Shut-off Solenoid ,lots of You-tube clips.
https://www.smokstak.com/forum/showthread.php?t=107195Cheers
Max