I had forgotten all about posting about this car before, (only 6 months ago https://justacarguy.blogspot.com/2017/01/the-z11.html ) and only had Mopars with aluminum panels in mind when reading Hagerty's article.
https://www.hagerty.com/articles-videos/articles/2015/04/28/louder-lighter-faster
https://www.supercars.net/blog/1963-chevrolet-impala-z11-lightweight/
https://justacarguy.blogspot.com/search/label/Factory%20lightweight