Did you use lead for the roof and quarter panel seam?? I just installed AMD full quarters on the '68 and the guy who will soon paint it insists that glass reinforced filler alone will suffice if the entire seam has been welded.
From my experience all metal or reinforced fiberglass will work on everything except for some reason "E" bodies. E bodies have to be leaded. If not as soon as it heats up the seam will show big time. Since I got burned by this I now lead all of them to be safe.
