Thanks again for the responses.
I took the fuel tank sending unit off this morning and took a look inside. Fortunately the outlet of the tank is directly below the sending unit and with a strong flashlight, I can peer right down into the brass outlet fitting and see all that bright shiny brass. I do not see any bits of debris sloshing about on the bottom of the tank either. My next step will be to remove the fuel line and pump and make sure they are all clear. And yes, I took the carb off and cleaned it out again and blew it out with compressed air. All seems good there.
I do not think it is a spark/coil issue since when it quits, I can start it again right away with a bit of gas poured into the carb intake - everything is still hot, or at least as hot as it gets during a 1/4 mile drive.
