Your pictures look exactly like all the 413 H.D. Industrial , marine and truck motor blocks I've bought and used to make 426 W motors, including the wired looking water like pump bosses on the rear
The last one, 413 H.D. truck block I took in trade was cast in 1972 and came with the H.D. crankshaft which I used the crank to offset grind it to make a 3.91 stroke crank with 2.200 rod journals and put it in a 440 block for pump gas street motor. I had a Mopar 8 bolt crank flange 4.150 stroke crank in stock and used that crank in the 413. block bore to 4.25 to put in my 1963 Plymouth Fury with a set of 440 source heads so I can tell the locals that old Plymouth has a 413 C.I. junkyard truck motor in it that runs pretty good for a 413
