I had to remove the covers off my rear armrests on my 70 442, this is what was underneath. I had to remove this insulation to get to the metal frame which was rusted. My question is this insulation material available or a good substitute? Thanks.

 

its available,was looking at it for my 65. get it from online mfgs,legendary,pui ect. get it thru upholstery shops also.

 

Strip all the old jute off, and don't bother with the padding kit that the resto places sell. Its not an exact match anyway and its a pain to work with.

What you want is called Sew foam, its about 1/2" thick and has a cloth backing on it. Any upholstery shop will have it and its very inexpensive.
You glue the foam side to the metal, cloth side facing the inside of the vinyl.
usually double up the layer on the the top / armrest side only.

It creates a very nice feeling armrest w/o being too padded.

Here are a couple that I've done...

 

Thanks 88 and RAMBOW any preference on the glue?

 

This is the stuff you want, anything else is going to come loose when heat is applied to it when the car is out in the sun....
Dap Weldwood Landau top adhesive

You can spray it or brush it on, works the same.

 

A 1000 thanks for saving me loads of time researching.