I made new floor pans from .125 AL and coated them with lizard skin on the bottom and I will use DEI heat mat under the carpet. I also made a
secondary firewall and insulated between the layers to control heat and to hide my AC lines up to the VA unit. I am still thinking about notching
and boxing the chassis tubes where the pipes pass through them so I can drop the longer muffs I used a bit further away from the floor panels.

BS
You should look at the newer mufflers that control heat better before you tear out that interior. Sorry I don't recall the name of them but there
is a thread about it somewhere.
DB