OK, I think I just used the last of my "little grey cells" but I found
the name of the guy who built a DOHC flathead
http://www.roadsters.com/flathead/#Davis
I don't know if I mentioned it but the Ardun heads
are being made by Ferguson in Wilmington Ca...
not far from me... I've been meaning to take a ride over there
and see his foundry\shop