gear ratios and torque

I currently have a 3.21 rear, with an A999 (wide ratio, non-lockup mod) and 26.5 inch rear tires, it's just about a dang near perfect all-around driver. I can easily squeal the 245/60 tires and she takes off pretty good. Then again I have a pretty built 360.

I did experiment with 3.55's once.
The change was not worth it, highway driving suffered a bit for little to no gain.

I agree with Rusty, changing rears is not going to magically get you more torque it just moves the torque range quicker or slower (depending which direction you go)

With my current setup I can cruise the highway at 70 mph and stay around the 3000 rpm range.
I drove to Colorado and back (500+ miles one way) and averaged 16-17 mpg.

Now I do plan on rebuilding an A500 that I have and eventually putting a 3.73 or 3.91 rear.