Could be a CMP (Canadian Military Pattern) engine from an Army truck. Ford of Canada was fond of that type of relieving the block, not so much for extra breathing but because they believed the thick metal there in the original casting led to heat cracks. They may have been right, we have several of these blocks and none are cracked! I can't see any of the typical cracks in your pics, either. Usually they are between the center water hole and the bolt holes nearest them. They don't matter much, but it's nice to see one without those cracks, since that is the first place they crack.