In a 5.0 with 5spd, 3.27-3.73 work great. In 4th at 6000 you are around 120mph, if you have the power you can pull 5th but it is a big drop in RPM. I liked having top end more so I had 3.27 in my 93 GT, 140+ in 4th and still quick in the 1/4.
My 93 LX would hit 119-120 @ 6000 right at the end...