found a way to install aftermarket drip rail molding on 68 mustang. Aftermarket moldings were too small and would not snap into place. Pulled a 1/4 inch screw head along the inside of the trim piece. Expanded the width by about 1 mm and they snapped on in about 2 minutes per side. Thought this might be of use to a few people who were having trouble making the new trim pieces fit.