I just checked Cross Canada in case they listed sheet metal for your car but no go.
I imagine a Catalina panel would be close enough that you could cut it up and use what you need? I am not sure, but I think there's a couple of members on here who will be able to tell you if that would work.
Oh, and welcome here. I saw your first post but forgot to say it in there.
I checked out your pics on cardomain. Very cool looking car.
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1966 Strato Chief 2 door, 427 4 speed, 45,000 original miles
1966 Grande Parisienne, 396 1 of 23 factory air cars
I have a pair that I bought many years ago from a member here. I understand they came from Cross Canada for a Canadian application but I bought them as patch panels for my 64 Catalina.
Never to late the more information the better I have been comparing pictures of the quater panels on the internet and I'am guessing All 1963-1964 full-size models Parisienne,Strato Chief,Bonneville,catalina, Star Chief, Laurentian have the same quater panel