Tips to install cardboard headliner?

If you haven't already done it, or thought about it, I would highly suggest placing insulation up against the roof before re-installing the headliner. There are a number of types and brands of products. On the two cars we rebuilt, my son and I used an insulation we found at The Home Depot. It looks like a sheet of bubble wrap layered with aluminum foil on both sides. Cut it to shape with scissors and either glue it or tape it up against the bottom of the roof. It's thin enough not to interfere with the headliner and comes in a couple of different width rolls. As a matter of fact, we covered the entire floors and firewalls with the same material for insulation and sound deadening.

Jerry