Loss of power after RP swap

[curvedglass]

I am new to the board and looking for a little advice. I recently purchased a 63 short wide which I want to take over daily driver duties. I like the 230/3 spd for efficiency however the previous owner swapped in a set of 3.08's. I am getting 19 mpg but I can't make it to the top of the hill without constantly rowing from 2-3 and best speed is about 45mph with the clutch chattering away. It just runs out of gear. I plan to keep this truck for a long time and as I get older clutching is getting to my knee. I am considering a 700r4 swap. My concern is that I will still be stuck with a truck that can't make it up the hills? Will the 700r4 make the truck a better driver, or would a 5 speed be a better solution.

I thought of hopping up the six but then I use more fuel and lose the mpg.