67 Barracuda outer wheelhouse installation question

Everything has been going good up until now. I am replacing quarters, trunk drops, rear valance, and outer wheelhouse's. All AMD pieces. Started removing the outer wheelhouse on the passenger side first, and I have ran into a funky continuous crimp style weld that connects the outer wheelhouse to the inner wheelhouse. I will include some pictures of what's going on. Any advice on how to remove the flange would be greatly appreciated. Thanks!

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