Rear end dilemma...

[BK'66Step]

So I just cracked open my rear diff for the first time in preparation for cleaning it up. I discovered that it has 3.08 gears! So my end result is to have a SBC 350 with 350-400hp, 700R4 trans, and 255/60R15 tires in the rear. I was wanting the 3.73 gearing but, if I understand correctly, the lowest I can get are 3.42 gears in a 3 carrier rear end. Does anyone have a similar setup with 3.42 gears that can comment on the drivability or suggest another setup. Any other thoughts would be appreciated as well. Thanks all!