Expanding foam insulation used to fill holes in the trunk. The PO of my cammer was a real bone head.
Don't knock the foam insulation trick - I didn't have any source to weld when I was 17 and had a crappy S-10 with rust all over. To keep the doors from leaking at the bottom, I had to fiberglass the hell out of them, and the best way to even out the body to be able to apply fiberglass is that crappy foam.
