I did the headliner in my 76 GMC about 10 years ago and it's still holding up well. I used the original headliner backing 'board' (foam, fiberglass, whatever it's made out of), some 3M spray glue, and bought some foam-backed fabric headliner material at a local Hancock's Fabric. It may start to sag or come apart tomorrow, but it worked well for me.
Good luck with your project.