1977 Chevy Caprice Engine Compartment/Wheel Well Protective

Engine Performance problem
1977 Chevy Caprice V8 Two Wheel Drive Automatic

I am trying to replace the "Composite" Sheathing/Shielding Material that's secured to the "Engine-side" of the Front Wheel Wells w/Plastic Push-Pins, and protects the engine from the Weather & Street elements.

I am hoping that you can inform me as to (1.) The "proper name" for this "Gasket-like" Sheet Material; (2.) The actual composition or make-up of this particular "protective" material; and, finally, (3.) Where I can obtain this material - either as a "custom" or "Bulk" roll product.

I look forward to your response.

Thank you.