the gm I6 motor also has continuosly variable valve timing...
thats why it pulls so hard all over the rpm band..

 

Well, continually variable exhaust cam only of 25 cam degrees. That works for emissions, part throttle power, fuel economy as well as full throttle power.

If intake closing is the most important event for power, the exhaust cam is the one to vary if you only move one. I believe the "NorthSouth" (longitudinal) Northstar V8 will have both intake and exhaust cams variable for 2004.