440 Automatic. What gears are you running?

I presently have an 8 3/4, 3.23 SG in my 72 duster. I have a mild build 440 with a 727. I have never driven it on the highway in the 3 years that I own it. All of the car shows and cruise-ins are within 30 miles of my home on local roads. 28" rear tires (275/60R15). Thinking some bigger gears would increase the fun factor around town. Not planning on taking it to the track. Those of you with a similar motor/tranny set up and tire height... what gear ratio do you run? Are you happy with them?