Slant 6 HEI problems

the spark check was both, checked it this morning, before start up, weak. Yesterday it ran amazing, very response, yes it does have choke, but bogged and died after 10 minutes of idling. Then I'd restart it, it'll run them slowly bog out and die. I used my spark plug tester to check for spark, was getting a very weak spark, when I test the wire straight off the coil, it gets a big orange/ whitish spark. But off the spark plug wire, very faint spark that slowly decipates.
"Bogging & dying" sounds like running out of fuel vs misfiring or suddenly shutting off, which is usually what failing ign. components do. What condition is the tank in, new
or ?? Make sure the tank vent is clear & allowing fresh air into the tank as the pump removes fuel, if the tank is aged, rust fines may be getting picked up and clogging the
sock. After the engine stops, the fines can wash/fall off the pick-up and allow the pump to re-prime/fill the carb..only to starve-out again.