I recently got myself a running 244, though it has had the Southern heat and humidity working on it for three decades. I've got a line on most everything inside that's a problem, except headliner (that, and who I need to hunt down and slap for the aftermarket radio and alarm wiring, but I'll probably replace the main wiring harness this winter, anyway). The current headliner is a hard layered board, about 5/16" thick, which sags and bounces, as it is only supported at the edges, where it rests on trim and the body. It looks like it was originally meant to be closer to 3/16" thick. The coated bottom layer, that you see from inside the car, seems fine.

Is it best to repair it, or replace it? In either case, what materials and/or methods work the best? I can search, but I get conflicting answers, some of which clearly won't work for this car anyway, and some if which gloss over dealing with wires and the dome light.