Had the same thing happen on a 454efi this spring. Cranked at home but at the ramp it was dead. After lots of checking and etc it was the starter. When I got it off and checked it with a pair of jumper cables nothing happened. Dropped it on the ground to jarr it and tested again and it worked. I still put on a new one. Cheap insurance if all your voltages check out good.

:Well it turned out to be a bad relay. Another friend with much better electrical skills than me found it.