That engine has an unusual breather tube that wraps around toward the rear. Maybe a car setup?
I'm going to make a SWAG (Scientific Wild-Donkey Guess) that the block has the threaded bosses for center motor mounts- - - -passenger car and/or Powerglide transmission equipped vehicles from the early 1950s. That would explain the offset road draft tube. It's supposed to be delivered tomorrow, so I'll do a casting number and serial number search once it arrives.
Jerry