Can this be done??

[hoodup]

Hey there all, I have a 68 3/4ton swb 350ci with a four speed muncie and np205 transfer case. My thoughts and questions are I would love to have a five speed tranny. with the 4:10 gears it does not to bad on fuel and rpms mostly due to the fact that I drive her with respect and don't hot rod around. that being said i feel a 5 speed would be a great addition to my pickup that I drive daily and year round up here in Montana. So has anyone done this? Or know what tranny would bolt up? and some pros and cons? Thanks in advance.