Fuel Starvation?

Try disconnecting the vac line from the distributer. See if that helps. On rare occasion, I have seen a bad connection in the dist, and when the dist loses vacuum, the advance plate moves, and cuts the ign.
Another question. Have you connected a fuel pressure gauge? What is your FP? Does it change when the engine dies?
I am running the progression ignition that uses a timing table like an EFI system. I have a FP gauge from Summit but it is very inaccurate so I removed it. I would not be able to see the pressure with the hood closed anyway. Maybe down the line I could install one that would have a gauge under the dash that I could see.