Beautiful Cuda!!
I noticed one thing that I've seen on many 67-69 Coupes and fastbacks , including mine.
The alignment of the rear decklid is off by about 1/4 inch where the mouldings meet the rear taillight buckets even though the gaps are perfect.
For what its worth, it is not the trunk gasket . Already been down that road.
Not sure if this can even be fixed as it was probably like this from the factory.
Anyone else run into this issue ??