My new home fabricated ram air

There are no studs. There are threaded holes. I had them repaired when I first installed the scoop. We used bumper glue and 1/4 - 20 threaded inserts. They worked for a year and a half. I re glued them in with JB weld and they held up to 120 mph. I am thinking of drilling a slightly larger hole, gluing in a threaded insert, then drilling through the bottom and pinning them in place. I need strength, and I want that scoop back on the car.