Left-hand piece, the larger section lies on the flat floor, the tapered section up past the rear light unit covering the wiring
Plastic push-in fastener, serrated, not threaded
Bracket attaches to the top light-unit bolt and the plastic fastener pushes in to it ...
... with dimensions
Bracket attached and ready for carpet and fastener
Separate chassis rail carpets fabricated and glued in as the arch carpets were not long enough to go over them. They were also flat and the only way I could get them to fit anything like reasonably was to cut a couple of darts in the sides. Note the darts have to be cut out, and not folded over as in thin material.
The V8 arch carpets, which I'm pretty certain are original, are not only moulded but the sides are long enough to go over the chassis rails and under the battery cover carpet. In fact the battery carpet press studs are riveted to the floor through the edge of the arch carpets.
'A' is arch carpet and 'B' is battery cover carpet.