A lot of the repo (and even SOME NOS) wheel opening moldings are a real pain in the butt. I have a trick that may help some of you. I use rubber coated spring clamps and secue the molding to the car before drilling any holes. As you can see, the clamps are perpendicular to the molding and fender edge. This forces it to fit against the fender. I then start at the top, drill one hole and secure it with a screw. From there I work my way out-one in front then to the back etc etc, always going back and forth. Sometimes if you get one thats really bad you can use a hammer and dolly on the molding to stretch it, just tape it up first to protect the finish. Patience and trial/error is the key to fitment on these cars.
Good luck, I got the clamps at Sears or Harbor Freight.