flathead ran with no oil

[Tom Walker]

Glennpm has it right. You need to get some oil to the mains and rod bearings, then take the plugs out and crank it on the starter till you get oil pressure on the gauge. Also stick some oil down the cylinders. The bearings will have got hot and maybe are shot, maybe not.
Before you do anything drop pan plug and flush some some fresh oil through.
Good luck!