In Reply to: 9N pto cap posted by Andy Wildman on September 14, 2017 at 11:16:54:
I have always thought that the very early ones were cast aluminum and than changed to the cast iron. There would be no reason to change the 9n-726 part number because they were basically the same only a different material. My '39 9n #7863 had the cast one as did my 1940 9n bought from original owner.
Over the years I have never seen an cast aluminum one on a 9n and I have looked. As others have said get the cast iron one and paint it and no one will be the wiser.