1940 Ford Deluxe X member sheet metal original thickness

[ford38v8]

Originally Posted by Kube

...the closed car outer frame rails were DESIGNED to be a nominal .100" thick and open car frame rails were DESIGNED to be a nominal .110" thick.

Considering the amount of documentation on the most seemingly insignificant pieces, I'd think something like changing frame member thickness would warrant a note on a drawing and most certainly an engineering release.

Mike, the documentation on the outer frame difference? Can you copy your source to the forum please, and what years did it cover?