Slant six exhaust manifold heat shield?
In the 80s when they started putting a converter right off of the manifold they started putting an asbestos looking white "plate" between the intake and carb, it actually was sandwiched between them, held on by the carb fasteners. After a few years these crumbled away.
Some cars also had that thermo guard over the battery. My 78 fury has this and unfortunately they built the washer fluid bottle into it.
My dad's 79 Aspen and my mom's 79 Lebaron also had this mom's car was a super 6 car. The fury and Aspen were 318s.
But being that you show the old RV 2 compressor I think you're talking something older than I am