? About using Dynamat on interior roof
 

When installing dynamat on the interior roof, should the factory insulation be removed first or do you just over top of it? Car is a 72 442 if it matters

You'd be best off removing it. It's essentially cardboard/fiberboard. Even though the dynamat may stick, it may not last long and that would suck to have it all fall down onto a new headliner.

The job is a total PITA, but with patience you can do it. I just sat in there for a couple of evenings with a paint scraper and went to town.

X2. And I remember reading somewhere the product is more effective if applied directly to the metal for some reason.

Thats what I figured...I just got finished...tried scraping with no luck used a 4.5 angle grinder and a wire wheel, made a huge mess but....still have to wipe it down and apply the Dynamat. thanks guys....

applied directly to metal is best. make sure metal is clean and use degreaser as well. when applying use a heat gun to further activate the glue. also another tip....after done applying....seal the edges with silicone and it'll last forever.