Originally posted by PowerJunkie
so how do you know what is the best rise heigth?
To the best of my understanding, it depends on how the rest of the engine is configured (porting, bore, compression ratio, etc.) and where you want the engine's power to be concentrated (low rpm vs. high rpm).

I realize that answer may not help you make a decision. But when I try and elaborate more than I already have in the original post, I start becoming unsure of the accuracy of my advice...