[novadude]

You cannot compare runner cc's from different engine families, as port lengths are different. The engine response to CSA (cross sectional area) changes. It doesn't really care about cc's. cc's are just a convenient way to compare CSA changes, since the cylinder head intake port length is relatively fixed for a given engine family.

My point was that the cross sectional area of the BBC L72 head is HUGE compared to even a large aftermarket SBC head. No reason why a 422 SBC with a 227 cc head can't be as &quot;civil&quot; as a L72 427 BBC with even larger ports. [img]<<GRAEMLIN_URL>>/wink.gif[/img]