Yeah, Vortec is not V-TEC.
Vortec creates a vortex within the combustion chamber which makes for cleaner combustion.
http://www.gm.com/automotive/gmpower...bout/index.htm
V-TEC changes positions of the cams to favor either economy or power when appropriate.
http://www.howstuffworks.com/question229.htm
I'm pretty sure the truck had something closer to Vortec, if anything, because chances are, it was OHV, ruling out V-TEC.
------
Every vehicle has a variable carburator/fi system. If your foot is on the floor, you're dropping the most fuel you can, if you're idling, the least, and then inbetween. As for your friend, he's most likely full of it.
The combustion "shape" is usually controlled by the shape of the heads, and your friends engine is not only 6 Cylinder, but also a Dodge, so, he probably can't get aftermarket heads for it. He could craft his own.... if he had really expensive machinery.