i have a 68 Charger project im tackling replacing the rear valance and end caps, i have a few questions...
1) What did they use or can be used to replace the foamy type sealer that they used to sandwich the parts before spot welding them together.

2) What did they use or can be used fill the huge empty cavity behind the end caps, it looked like some globby epoxy, im thinking of that expandable foam stuff?

3) How can the seam that attaches the cap to the 1/4 panel be welded or tacked. I will supply a few pics , any ideas for those who have done it.