A while back I replaced the windshield channel on my 66 gto. The car has since been painted and put back together but the painter did not seam seal under the new channel like I asked him to. So there is a bit of a gap between the new channel and the piece of the firewall the channel sits on, allowing water, air and exhaust to enter the interior. The caulking seam sealer is too big to get it where I need it to go and I tried putting some on my finger and spreading it but that didn't work either. so I am wondering if anyone has an idea on how I can close this gap. Thanks in advanced.