He explained it in that post. When fuel is being sucked from the tank, it created vacuum and eventually it will stop being able to pull fuel and it’ll starve the engine.
Think about pouring gas from a gas can that doesn’t have a vent at the back of the can, what happens? It sucks in and collapses.
Rebuild in the works. New crank, 2013 Boss rods, srp .020 over flat top pistons with valve reliefs, 12:1 compression, ported pi heads, comp xe278ah cams.