Just finished my spring over on my 86 tintop and I have a pretty good vibration in 4wd. In 2wd it goes down the road smoothly so the rear axle is ok. Just to clairify, I welded the perches parallel to the old ones at all four corners...and I double checked this. I don't have any driveshaft spacers yet either. I have fixed hubs on the front.  Any ideas what the vibration is from? Another funny thing is I hear clicking from my wheels when I turn the wheel sharp right or left in 4wd. Before the Spoa I didn't hear any clicking from the front. Could I have got my axle too hot when I welded the front perches. I never took the axle apart before the Spring over...any ideas? 

The vibration is normal, put locking hubs on it and live with it. I drive mine in the winter in 2wd.

fullspectrum,

When I did my SPOA on my old SJ I also put the FRONT perches parallel with the old mounts - this is a good way to keep the castor , camber correct and the "U" bolts still bolt up OK.
Out back however I kicked the pinion up so it pointed straight at the T-box flange. This is very good for UJ angles and I experienced ZERO vibration in 2WD or 4WD.
You MUST run drive shaft spacers though because the male spline moves so far out of the female spline that it starts to get really sloppy ( climb under your rig and push up and down right at the slip joint - if it has up and down play then sort it out real quick ).
I personnally went down to a tractor parts supply store and bought another longer section of female spine and welded this on to take up the slack - spacers would be easier though 
Locking hubs - very good advise, get some.
Clicking -     
Good luck 

ZeusZuki 

  Thanks for the replys...I can live with the vibes in 4wd as it will be 80%trail and 20% road. I'll get some spacers asap. DOes anyone have a pic of a Samurai front pinion angle before a Spring over? I forgot to take a pic myself. Just so I can compare it to the angle I have now which is almost pointing at the t-case... at any rate it looks alot better after the Spoa...