Mounting a dual snorkle Mopar scoop

My scoop has been used and I am not satisfied with the holding power of the mounting screws that thread into plastic inserts in the fiberglas studs on the scoop. Was thinking about filling those studs with some sort of material that I could drill out to the correct size of the fasteners that I use (by the way, what fastener is best: sheet metal screws or bolts?). I have read that JB Weld can be drilled, but its pretty hard and may crack the fiberglass if I dont get it drilled just right, so maybe something like Form a Gasket non hardening formula? I also considered using Loc Tite.

thanks, George in Tallahassee