I'm not that familiar with the newer Ratios, but in '55 to '64, a good all around gear today would be a 3.36 or a 3.55. The 3.08 would give you the lowest RPM on the highway. A little daring would be a 3.70, but I wouldn't recommend it if you plan to drive at high highway speeds.
I believe there is actually some charts out there that will show in better accuracy.
-Parting Out over 75 '58 to '73 Full Size Chevy Cars-
-National Impala Association
-Vintage Chevrolet Club of America