.02 on keeping your insulation off your headers.
I applied a noise dampening mat to my firewall down to where the body mt is under the front floor boards.
It's been there since about '93. I used vertical lines of masonry high heat caulking (vertical lines of caulk to allow moisture to run down and out after deep water crossings) about every 4" and used pop rivets with large "backup" washers in a few critical areas. It looks the same now as it did on install. REALLY helped with heat on the pass floorboards before I did the body lift and ceramic coated headers later in the 90's...
I applied a noise dampening mat to my firewall down to where the body mt is under the front floor boards.
It's been there since about '93. I used vertical lines of masonry high heat caulking (vertical lines of caulk to allow moisture to run down and out after deep water crossings) about every 4" and used pop rivets with large "backup" washers in a few critical areas. It looks the same now as it did on install. REALLY helped with heat on the pass floorboards before I did the body lift and ceramic coated headers later in the 90's...