Let me get this straight, the VTEC-E runs on only 12 valves until the vtec kicks in then all open. And the regular sohc vtec (ex) runs with all 16 valves open even before vtec kicks in? If thats the case, i would think that the ex head would be alot better.

 

yeah, thats pretty much it. the other valves move a little tiny bit to keep fuel from pooling up around them, but then they open up at the changeover. and the ex makes a lot more power, but the HX gets WAY more mpg, with the one valve per cylinder just barely opening, it makes a swirl in the chamber that mixes the air/fuel well enough to be able to run REALLY lean, thats where the mileage comes from.