Any suggestions on this? Actually it's not necessarily a seal but something to prevent the fiberglass from rubbing together when the engine hatch is closed.
I bought a roll of 1 1/4 foam with sticky on one side that lasted about a day. Needs to be more durable.

Here's a pic of where it needs to go. You can see some of the cheap stuff I tried before.

SM, my guy used a rubber gasket that campers/motor home companies use. Sticky one side, came out great. No leaks either.

Try you local auto parts store for different types of weatherstipping for different applications. The local stores here have rolls of various styles of weatherstripping and can cut it to length for you. Probably similar stuff to what Waterheater was talking about.

Thin piece of lexan or plexiglass either glued or screwed in place, kind of works as a "stop" and will last longer than any rubber gasket.

try this company. I've used their products on boats , cars , whatever it is they have a seal or moulding. http://www.trimlok.com/

Ive got some 20 mil film in 3 inch widths, let me know how much you need Joey, I give you special price...seriously, let me know and I'll ship it to ya...Rob