Is that blue styrofoam? The kind that burns and gives off noxious gasses when it does? You might want to replace with something less flammable and toxic if that is the case. We found mechanical fasteners - essentially nails or screws with big fender washers on them- the most secure method. The ones in the kit Soundown Noise-Reduction Mounting Kit have a square base that gets epoxied to your wood cover so the nail sticks out. You then put the foam in place, piercing it with the nails. The washers hold the foam and the caps keep the washers snug against the foam.

 

Any impact adhesive will do but yep looks flammable to me ! Try finding some automotive sound proofing thats self adhesive and non flammable.

 

Thanks. Hmm.. not sure what it is. It's not blue - it's a black and white multi-layer product with a textured black outer layer. The same product covers the whole interior of the engine compartment and looks to be original.

 

When I Did my engine with soundown. I used 3m spray adhesive high strength 90 in the green can.