If engine is out of a truck,it's got some parts on it with the letters 8RT, like the water pumps. Please post more photos showing both side, front and rear of engine plus top and front engine mounts.
The casting numbers you are showing are not going to tell you much. There may be some numbers stamped into the block around the intake manifold area. Date code stamps.
I've never seen most of these markings on a United States-issue Ford or Mercury engine. Even that stamped-steel half-bell is kind of foreign looking. Is this truck in the contiguous 48, or Alaska? Let us know what area on the planet you're writing from. In fact, can you please send a better picture of the transmission? DD
If the engine was replaced it looks like the a truck intake was used and the heads may have been replaced with generic Ford heads.
You may or may not be able to at least determine the year of build if there are date codes stamped on the intake manifold mount surface.