From the bottom. I removed the bottom two ribs..........
I carefully pried off the rocker mouldings, taped them down along the top few lines and used a razor-saw flat along the length, carefully sawing off the bottom two ribs. I then ran the rocker moldings along a fine file, and finally finished the new bottom edge with aluminum muffler tape, although chrome paint or BMF foil would do the same edge finishing. Any picture of a '58 would show that DM's rocker moldings are much too thick as produced. I'm surprised that the moldings didn't improve with the subsequent introductions.