under carpet foam.

[paulie71]

just a word of warning about sourcing backyard solutions or adlibbing with what you have (eg: newspapers etc.) Remember that most of the materials used in a car (even as old as the first Mk1's) may be fire resistant or have fire prevention properties.

I would suggest avoiding any material you feel might increase the likelihood of fire spreading inside the cabin. Yes there is fuel and/or oil and/or sparks in the engine bay and/or under the back seat, but these are exterior to the cabin. Newspaper is side the cabin as underlay might not be too fire resistant.

[pepperwhite]

I used some super lightweight foam panels from reverse garbage in brisbane. $5 for enough to get all my carpets fitting right.