Well, this last set of changes at most 1.5-2hrs a port...maybe not even. All I really did was to remove the left-over valve guide boss casting that sloped away and into the roof...I tried to make that as "steep" as possible by basically removeing as much of the material as possible but without joepardizing the guide support that's needed. It is by no means nowhere near some of the pics I've seen floating around where literaly just the guide itself is left in place. I'm just not that brave...LOL...