A contact cement like 3M trim and weatherstrip adhesive (gorilla snot) would be my 2nd choice, after a thickened epoxy like G-flex 655 or the Six10 that comes in a caulking tube.
All of these are formulated for a flexible weatherproof bond.
Cleanliness is a must and some abrasion on the back of the strip will help.
Like sand with 60 or 80 grit and wipe with alcohol until the paper towel comes away clean.
Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.