After 23 years the insulation in the engine bay was flaking off, so removed and installed new the sides are 20ga mild steel so the magnetic backed lights stay were you stick them, insulation is 1" of Rock Wool, hope that will be enough, the top hatch is a sheet of 5052 Aluminum with 1-1/2 x2 angle with 2" of Rock Will still have a little clean up to do, I still need to...