The padding is just to level the floor off. The metal pan is full of dips and grooves, so just fill them in to make the floor level.
If this is original padding I would toss it and get some newer aftermarket fire resistant padding. I know of more than one car where the exhaust caught this stuff on fire where it burned the exposed padding under the driver side where floor board was compromised. I actually use this stuff as fire starter in my old cook house! While I like staying original as I can, there is much better material out there now that is fire resistant and provide better sound proofing.
Thanks for good reminder! I plan to put some sound deadening material to floor to resist heat as well.
When purchasing new carpeting you will be given the option to have it rubber backed or not
I had it rubber backed
The rubber back will help with deadening sound and be water and coolant proof ( for when the heater core leaks on you ) and a new sound proofed fire proof material would go under that for the best case
I second Jason’s concern about the stock carpet backing catching fire from the hot exhaust pipes under the metal flooring of the car as it did happen to me on the rear seat drivers side long ago
Of coarse any rust holes in the flooring will ( driver side only ) cause the carpet to to be more exposed to the exhausts heat and increase the problem of a fire there
I was surprised how reasonable replacing the cut pile carpeting in my 64 convert was to purchase and a very very nice upgrade to be doing
Of coarse — my heater core started to leak a little while after I installed the new carpeting but it did cleaned up very nicely
Life has a way of doing Crap like that sometimes - Grin and bear it is best you can do sometimes