http://en.wikipedia.org/wiki/Cylinder_head_porting

Its a good read with real info. intened for newbies and the knowitalls.LOL

 

Cool thanks for the reading. SCHOLLE

 

There are more variables than what is discussed there.Air speed/velocity comes more into play than shear volume. My umm Raptor head is jamed full of valves already so there was no real need for bigger.The stock intake path sucks though. I have looked at a couple of DS heads (pictures) seems to me going much if any bigger would have any real benifit? Unshrouding and maintaining the chamber shape is engough without having to remove even more material. I guess thats why there has been some success with the big bores with big valves.