Bought mine from JC many years ago. It did not fit well at the corners/edges. There were gaps.

http://www.1954advance-design.com/SubHeadliner/index.html
(on the second page are some photos of the insulation I installed)

ALSO, I suggest you seal the edges/back of the cardboard with epoxy/urethane paint to help to decrease moisture absorption and the resulting distortion of the cardboard. When the cardboard distorts, it drops out of the metal "divider" strips between headliner pieces.

A member reported a few years ago on his project to make those panels out of plexiglas, so as to not worry about distortion after installation. I'll look for that post, and post a link here if I can find it.

Here is the thread with Mark's nice work.

Also, Here is a thread about metal "stays" to keep the cardboard flat. They usually "disappear" when the cardboard falls out (and/or is removed).

Last edited by tclederman; 11/16/2017 3:43 PM. Reason: added link to Mark's nice job, and parts from KC Mongo