Many discussions on this subject. I personally have not researched but some insights in other threads.

https://www.stovebolt.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=581290


~ HB
1966 Chevrolet K-10 | Ghost: formerly Flappy Fenders | In the Stovebolt Gallery
1962 Chevrolet C10
1962 Suburban