If you keep the original axle, torque tube, I believe 3.55 is as fast as you can get?
If you keep axle housing and swap center section, open drive line, what ratio choices do you have? 3.73 I'm pretty sure, and 4.10, but anything faster?
You speak of 3.08 and 3.32 ratios, but what rear axle would you get those in, a Ford 9"?

I believe to help narrow your choices you can weed out the impossible ones, and the expensive ones if budget is a contributing factor.

This is a nice gear calculator
http://www.onlineconversion.com/bigger_tires.htm

In my experience with the old Stovebolts 2500 or there about is a comfortable RPM on the road, and they will do more but not as fun on long trips at higher RPM.

First though, just get running and driving with what you have (or another 235 or 261, easy swap) and drive it for a good while, perhaps years.
Then you'll better know and understand what changes you desire based on actually driving the truck, not guesstimating and hearing different versions of what works for different people in different situations.

Grigg

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
---All pictures---
"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-