Those pictures caught my attention too!
Here's the original headliner thread... looks like .090" abs sheet.

Another question for Mark:
What is the shiny insulation you used behind the ABS?

PS. here's an amazing website all about automotive sound deadening:
https://www.sounddeadenershowdown.com/understanding-vehicle-noise
sounds like big results = big money

Last edited by Ott3r; 02/10/2020 4:51 AM.
'59 Chevy Suburban, NAPCO