383 Cruising Issue

Mattax said
If its backfiring in the exhaust then there is unburned fuel there, plus enough heat to ignite it of course.
Running out of fuel it sometime coughs and then dies.
Take out a few spark plugs and see what they have to show.

I don't think it was backfiring, and the tank probably had 15 gallons in it when this occurred. The spark plugs are practically new.