Yes to both questions. They are not especially common compared to the normal sized versions, but offer a slight power increase-likewise the 1cc version of the 75. Given that they are only 15% larger in displacement-(in the case of the 1.5 version)-you're not going to see much of an increase-and I would not be surprised if the generally variation in output you get with small engines would potentially obscure it-ie a 'good' 1.3 might well outperform an 'average' 1.5 variant...but the converse also applies...whereas I would expect to see a greater difference in output between a '75' and the 1cc version of the 75. The same arguments about variability however still apply.

ChrisM
'ffkiwi'