What year is this V8 flathead engine?

[Bruce Lancaster]

And I mis-arranged my notes...The so-called raised service was '41-WWII, the side ridges down to the plugs (on the pan rails of block) was '39-40.
You need to remove a head to spot whether 221 or 239; The arrangements of water holes at center will settle this even if it's a 221 bored to 239!
'39-40 239 generally had the "99" designation stamped in 1/4" characters at right front of the block's upper service. Obviously easy to fake IF anyone is profiting by telling you it'd a Mer.