Wet Brake, Dry Brake (Left Brake, Right Brake...) - 64 Valiant

Those foam gaskets aren't absolutely req'd. Thats what they used between cast iron and sheet metal like mater cylinder to firewall, backing plates to spindles, rear bumper braces to body, sandwiched sheet metal in general. detroitmuscletechnologies.com might have them. They're cut for common foam packing material so you might cut out your own.