4.10s would help your auto get up and go for sure. You will have to make a compromise between faster acceleration, rpms, and gas mileage with any higher set of gears.
True Blue has the right idea for cars as old as ours. Check out the front suspension restoration kit from mustangsunlimited.com. I have a 94 GT and am in the process of replacing inner/outer tie rods, front sway bar links, ball joints, all for 95 bucks. Sand off any surface rust off from...