That line is difficult to see in the quarter and fades away. When they did the block sanding on my car I made sure they knew it was there. They put tape above the line and sanded up to it; then put tape below the line and sanded down to it. This way they did not diminish, move, or erase the body lines in the process. There is also the line on the C-pilar on the notch that is a little more obvious.
I used to have a '68 Barracuda convertible over 30 years ago. I always thought something was off. When I started stripping multiple layers of paint and bondo I figured out that they had shifted that body line on the fender, door, quarter up an inch or more in the process of mudding the car with bondo. It was almost Camaro-ish.
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