Technical 1954 Chevy sedan firewall

Since you guys have been a Huge help to me in the recent past , thought I would ask another . While restoring my heater assembly , the firewall pad crumbled to pieces ( AHHH Shittt!!) So I pulled it all out and am wondering what to replace it with . New pad NFW! Paint POR15 & Dynamat ( possible but tedius and will it be thick enough?) Firewall pad really spaced out heater from wall also ( do I need that spacer for heater ?) Any ideas , would love to hear something helpful other than sell it , LOL. Thanks for listening Hamber's !

 

https://www.nationalchevyassoc.com/4711

Some of the vendors sell replacements.

 

If the metal is rusty use the POR 15. Then the dyimate type stuff. Then the repop firewall pad

 

Thanks , I thought the firewall pad might be a bear to put in as I have the Walton Fabrications firewall mount brake pedal assembly installed , guess I could trim here and there. Thanks