Advice on 61 rear end solution

[SMR]

Hello everyone, looking for advice on making my recently purchase 61 LWB C10 more highway friendly. I’m running the stock 283 motor (with edelbrock 1403 carb), automatic 2 speed powerglide, 29” tires and , what I’m told, is either a 3.92 or 4.11 rear end. I’m pulling about 2k rpms at 40 mph. I would like to be able to travel at 65 or 70 without having the motor work so hard. I understand that I can switch out the rear gear set to a 3.38, which will enable me to drive at higher speeds at more appropriate rpm levels. My question: Will this solution be sufficient to achieve my objective and are there other concerns I should be made aware of that may be the result of making this change to the drivetrain. My second question: Is there better solution that would be on par with the cost to switch out the rear end gear set?

Your help is greatly appreciated