Carl,
I'm curious to know what RPM do you normally cruise at? I typically don't have the patience to pull back on the throttle very much especially headed against the wind...come to think of it I like to speed along with the wind as well. I fly a '74 150L. I'll typically fly lower headed west to minimize head winds and much higher headed back east to take advantage of the higher tail winds. I still average about 5.5 to 6 gallons per hour. I once flew from Summerset, PA to Port Clinton, OH on full tanks thinking that I had more than enough fuel to fly the 210 nm. When I landed and re-fueled, the plane took about 19 gallons. I had experienced higher than expected head winds which taught me to keep track of fuel in terms of time instead of miles.