Thoughts on vibration

scampy said
I really don't what to pull the center section out again and put my 4.30 back in knowing I don't really want to run them,I just don't know what in the rear would cause this vibration,i'm not getting any noise from it,thinking of sending drive shaft out again for balance check,still gota check the trans mount,remove it, don't see anything mounted in frame,axle bearing???

my car had a similar vibration. turned out that the yoke on the diff was somewhat loose up/down (radially) and i had to set-up the gear again with shims, meaning the pinion preload was off. it took a while before i found it out. wishing this could help.