What are the differences between a 440 Marine Block (M440) and a non-marine block.

I assume that only the internal rotating assembly would be different, but would there be anything else different about the engine block, casting, etc... Are they a good block to use for rebuilding ?

Is there anyway to tell a Marine Block from a non-marine block (BESIDES) the M440 stamp on the pad ?

Does it use the same crank (it has a forged crank)?

Thanks for any info
Mike