We have a 72 we are working on. We got the rear filler panel and it sets in nicely but we have a question: along each side of the panel, there are gaps which will allow water to get into the trunk. What should we put there to prevent this? Thank you.

 

I think Chevy just used seam sealer on those gaps. Use a caulking gun to fill the gaps completely, then wipe off any excess before it sets up. Then prime and paint.