I have a k5 that is almost finished (not ever finished, but you know) it has a 6" lift on it, I have not driven it since the lift, waiting on my new axles. It currently has a 700r4 with a np208.
My question.
with that lift, will the slip yoke 208 cause vibration while driving like it does on the jeeps with the 231's? I have a np205 and the A.A. output shaft if i need it.. Will i need? I know all about one t case being aluminum, one being steel, one having a gear drive, one having a lower gear etc.. Will the slip yoke cause vibration when i drive highway speeds with a six inch lift..
Thanks guys.

A slip yoke will not cause vibration, wether it's in a Chevy or a Jeep.
The reason a Jeep with a slip yoke & too much lift has vibes is because the driveshaft is too short & the u-joints are operating at too much angle. Eliminating the slip-yoke adds a few inches to the shaft length & allows the installation of a yoke for a C-V type shaft.