It they were Formals...
I'm using the engine and trans out of the 71 for my 69. The 71 is a parts car. Everything works. I drove it back from Carlisle 250 miles. The interior is perfect. The nose is perfect. The bumpers and grille are mint. Tilt tele column, rim blow wheel. Power windows, which all work. Plenty of great parts on it. You pay 3 grand for the 2 door, it goes free (hows that Mr. it doesn't come with a motor?).....Its all how you look at things. I don't think Imperials ever came with a formal roofline.
The main car...the 2 door, is running and driving. Follow the bouncing ball man........
I would rather fix a few minor mechanical issues then rust. Now it runs from an external tank connected to the fuel pump. It probably runs better then anything you have.
Like I said...the firewall issue was always stated. Don't worry man....sell all your 68's.. I'll give you a good deal on my 70.