here, play around with this calculator and get an idea what a gear change will do for you. Speed/Tire/RPM calculator
our dart has a mild 360,low gearset 904, 9.5" converter,25.5" tire and a 3.23 gear. we just drove it 3000 miles. does well at 70 mph which the calculator says is about 3000 rpm. any more then that the mpg drops and while it will cruise at 85 mph it feels like you are pushing it. the car really likes 50-55 mph. runs nice and quiet and the MPG is about best there. with a 2.76 at the same 3000 rpm it should put me at about 82 mph. for me i know the car will still have plenty of pep around town for what i want. and even then i really only putt putt around town anyway and on the highway it will be a bit more comfortable in my opinion. but i know what i want from this car. I built the engine for what i want to do, i don't care about the track, its a pure street car that i want to drive anywhere i decide i may want to go.
again don't discount a 2.94 gear. depending on tire size that may be perfect for ya.