This time of the year it is common for fuel filters to freeze any water in the filter element and block the fuel flow.
If it is not the filter, and the fuel pump is not pumping fuel, the 460 Ford engine vans have a fuel valve that shuts the fuel pump off. It gets bumped, or a jolt of electricity from disconnecting and reconnecting the positive battery cable, an errant radio signal from a high powered CB, or from jump starting, the switch shuts down. Should be found under the right side kick panel. Reset instructions are in the owners manual.