I have a 67 Coronet that has been restored. Has anybody had any problems with exhaust coming into the interior at speed. I'm fine unless I'm going over 40 mph with the windows down. I start to get exhaust smell in my interior. I pretty much sealed up my trunk everywhere else but I do notice that my trunk pushes down a bit after it is closed so I'm assuming it's not sealing on the new weatherstripping. Anyone ever run into this problem and how did you solve it. I was going to adjust the latch down 1st. Not sure if I can move it back because it is lined up already.

Is there a thicker brand of weatherstripping I should use?

Do your tailpipes go straight or angle down...
I had the same problem, when I change my tailpipe for angle down like original no more exhaust smell.

I suspect the trunk gasket is leaking due to\
1 previous body damage preventing the seal all the way across the back
2. wrong trunk gasket
3. trunk gasket installed wrong.

When setting up the gaskets we use a sheet of paper. IE: close the lid with the paper between the lid and gasket, then check for resistance when trying to remove the paper. pay particular attention the rear sealing area as that is usually where the exhaust gets in. Same trick works on windows and doors too
Another messier way is to coat the gasket with a thin layer of Vaseline close the trunk, then reopen and look for areas that it was not transferred to

Thanks for the ideas guys. My tailpipes are straight, but I would like to try and fix the trunk seal before I mess with the exhaust. Thanks for the tips.

Just like to let everyone know that adjusting the locking mechanism so the trunk closed tighter solved the problem. Now my lid doesn't quite line up. Sounds like a winter project cause now I want to drive and enjoy.