68 Barracuda rocker molding

Yah was thinking the spears only, not the gills. I will drill the holes for those. Thought I remember reading somewhere that they filled the spears up with spay in foam and then used that black 3M body tape???
If I attempted that I would fill only sections of the spears with something like 2 part epoxy. Something that will set up hard and non porous so the trim tape will bond to it.