This is on the sill plate on a 73 Fury 4 door. Penetrating liquid didnt budge it, and when I used my drill with Phillip's attachment, it just stripped out the head so I can't get anything in there. I'm thinking the Ziebart material cemented it in place, but the outer two came out with a little effort. Do I need to drill out the screw? I guess I can always put a new one in and epoxy it in place so it looks good.... I really need to get to the seatbelt retractor.