Other than the unique outdrive section, just what makes a Volvo Penta
"engine" any different than a Mercruiser? Both are based on a GM 350
engine block (for most applications).


The marinization parts (externals) are different, the internals would be the
same. Things like fuel delivery, sea water delivery (cooling), exhaust, and
electrics would be unique from Volvo to Mercruiser. Block and internals
such as pistons and crank should be the same.