hey Chas, just to clarify the east/ west, north/ south thing, it's got nothing to do with the engine it's self but the way it's mounted to the mower, buckets twin is mounted what is called north/ south, the head facing the front, and if it was east/ west it would be mounted sideways, the head to the right usually. Greenfield only did this on a model or two in an attempt to make the mower a bit shorter.
as i mentioned before, the old side valve motors arn't being made anymore and the new OHV ones are bigger in size, so can course problems with space, you would have to sit a potential replacement motor on your mower to see if it fitted.
