Engine identity

[blucar]

I was recently re-arranging some "stuff" in my shop, I pulled out an engine that I had acquired many years ago. The stampings on the engine are not anything that I'm familiar with; The bore is 3-3/16, heads are 59 AB, block has, E27722 M.. cast into the bell-housing, with a very faint 59 that is very hard to see a couple of inches below the casting numbers.
I would appreciate any help to identify the engine..