The Belvedere is a 57. Looks how the side painted trim finishes in your thumbnails and how finishes in '58 http://www.plymouthcentral.com/files/58PB4drHT.jpg
The Imperial is a '66 http://www.imperialclub.com/Yr/1966/index.htm

http://www.imcdb.org/movie_57752-Gomer-Pyle,-USMC.html

I have added some of your thumbnails. Extra pics can be added by you.

PS amazing classics :king: