Finally got a chance to catch up on my reading the other day. Was looking at the August 2006 Chevy High Performance where they tested 8 heads on a 383. I was totally surprised when a lot of the 170 cc heads actually were 180 cc's in volume. 180 cc heads were coming in close to 200 cc's! Made me stop and think about what really is a good port size for a given combo since a lot of head's ports are actually bigger in volume than advertised. Anybody have any thoughts?