I had an opportunity to visit "Special Collections" at the
Iowa State Library and found the original Thesis done by J.T. Kulhavy
and Maurice McCann in 1934 on casting and machining 4 valve
heads for a 1920's JDH. I scanned all of the photos
and a few pages to share with you. Unfortunately there weren't any photos
of the heads mounted on the JDH so hopefully they actually finished it.....
A copy of the thesis is on the shelf in the library so if you ever want to see
it for yourself it's just a quick ride north!