wavy gasket?

Get the interior finished (headliner) and we'll go from there. I just installed mine in a 67 cuda and I have "waves" in the same area and my headliner is installed. At first I was pissed but over time they have settled. I haven't tried using a heat gun yet but will eventually. Let your car sit out in the sun and get real hot if that is possible. You will be amazed what that alone will do. good luck