Goodbye 3:73's

I'm swapping out my 3:73's for 3:27's this week. I recently moved 35 miles from my work and my gas bill sucks! I put about 70 miles on my daily driver LX and I can not make it through the week without refueling twice. I've been getting about 260 miles average per tank (all freeway driving). Rpms are at around 2600 at 75-80mph. And I baby the it too! No passing, NO downshifting just cruise everday to work.
Before I moved to this new place of mine I only had to drive 1 mile to work. Usaully I parked the car at home and I would walk or ride my bicycle to work.
Now that my car is a true daily driver,I'm starting to see how these gears suck up the gas!
The 3:27's should drop the Highway speed RPM's significantly to save me fuel and some extra $$. I'm doing the work myself and using a good set of gears that I have laying around. If I ever move closer to my work, the 3:73 will definetly go back in because they are awsome!
Anyone still running these gears in their Fox Mustang? Input would be great.
Thanks
Danny

Yeah I know I will hate the downgrade in performance. I went from 2:73 auto to 3:73 manual and we all know the difference that made. I've had the 3 73 in there for three years already. The 3:27's will be temporary, gear swaps are like a "walk in the park" for me so I'll switch if I can't handle the crappy performance.
Already have electric fan conversion (no dramatic fuel consumption changes, less noise though), underdrives, free flow exhaust and just about everything to make the car fuel efficient.
Someone mentioned the "drone", I don't get that awfull tone because I have the Delta flow 3 chamber flowmaster system with x-pipe.

cleanlx your probably right, but for now the gear swap is the most easiest modification I could do to get better gas mileage. Motor is super strong and clean to tear into.