gear ratio / rpm question

[slugish]

Hi fellow trucksters. Ihave a 350 turbo 3 speed trans. with a 3.08 rear end. Ioriginally put a 3.73 in it but wasnt too good for cruising. I took it back to my trans. guy so he could change to a 3.23 (sort of split the difference )he said 3.23 ring &pinion wouldnt work so he put 3.08 in it . Of course I LOST a lot on the bottom end. Ican cruise 60-65 mph now at about 2000-2200 rpms. The best of both worlds would be a 700 4r trans. with 3.73 back in 9WHICH i still have) Money is the problem here. Can anyone tell me if a 3.42 would work & what rpm would it be turning at 60 -65 mph. Ithink there is a web site with a chart somewherethat would tell me. Igo to the strip sometime as well . any help appreciated.