Okay, now I remember. I was searching for almost the exact phrase as the title of this thread. The difference is that I wanted to know exactly/as close as possible with the present technology, how much of an increase for a .010 overbore out of a 200cc jug. I first thought maybe there was a chart somewhere that would give some ball park figures. After thinking about it, i'm sure there are way to many variables for such a chart to be viable if it existed. Maybe a general formula? I slept through Algeria.