HEI issues?

[zachste]

So driving yesterday was fine for about 10 minutes, came to a stop light slowing down, and truck shuts off like I turned the key off. Try to crank it back over and just cranks and cranks (sounds normal though). 1 minute later on the phone with the wife to come pick my boy up (he was riding with me), and I turn it over and it fires up.
Finish my trek a mile to Home Depot, return some lumber. Fires right and runs great when I'm leaving. Stop at the grocery store and fires right up leaving there as well as the rest of the way home.
Took it out again later that night to run a couple errands and ran like normal.
Did some poking around, no loose grounds, or hoses, or plug wires or anything. I am going to re-check the wiring and connectors on the distributor tonight, and maybe another look at the grounds.
After doing some searching I'm thinking maybe an HEI issue? ICM?

350/350 (thumpr cam, edelbrock carb, 2k stall converter and shift kit)