Very troubling indeed.
Do you even know if it's electrical, and not fuel?
Could be a LOT of electrical things.......
Primary power supplying ignition. You could "rig" a pilot lamp at the junction of the supply voltage to be sure it's getting power. Check over your connections
If you are using a breakerless dist. make sure the unused "white" wire is not shorting
What are you doing for a tach? There should be NO connections to the coil, NONE, except the two wires from the MSD
Breakerless distributor? Could be there, including the connector
Bad MSD box, certainly. Go to their website, there is troubleshooting info there
Bad coil. You bet.
HOW to find?
FIRST make sure it is NOT fuel. Mechanical? Electric pump? That makes a difference
Might want to consider "rigging" a pressure gauge, even temporarily
You have a known good "stocker" coil? I'd just swap that in for a while "and try."
Distributor? You have anything else, even points? You can trigger the MSD with points so you could swap that in. Check the distributor CONNECTOR. Work it in / out, feel for tightness, inspect
Inspect the cap and rotor for problems, look over the reluctor and pickup for damage, debri. Check the reluctor gap, .008" (inches) with a brass feeler.
MSD box? Crap shoot. What else do you have to swap in there?
