Engine block I.D. MMM-?

["Scotty" <scotty@dove.net.au>]

Fellow listers,
                        I have recently aquired an engine block which
resembles a J2 block, can anyone help identify this lump of metal?

cast on the side above the small raised engine # is
174184E MMC { The E after the #4 could be a C }

Engine # is 13497  A

On the face of the block upside down # is 5074.

Enquiring minds wish to know the lineage of this treasure. 8^)

Regards,

John{Scotty}Scott,
Adelaide,Australia.