What year is this V8 flathead engine?

[Bruce Lancaster]

First sort: Look at block/intake manifold join...is surface of block continuous all the way across, or are edges lower than the space under manifold, which would be an almost manifold-gasket shaped platform? '39-40, doesn't seem to be a '38.
Are there two ridges down each side of block, leading to a slight bulge in the pan rail... there would be freeze plugs visible there if you removed pan. '41-2-WWII
Beyond that you need to remove a head.