Dauntless;53749 wroteI think all B230s have B230 cast into the block in large letters behind the drivers side engine mount. I don't remember seeing anything there on B23s.
They look a bit different too on the starboard side.
B23 (from Angus' page) - note the lack of 'ribs' near #3 and #4's welsh plugs

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B230 non-squirter block at same perspective - note the 'ribs', the clear 'B230' marking, and the lack of bumps along the oil gallery

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B230 L-Block (squirter block) - note the little bumps along the oil gallery