I just put a 4" lift on my 85 RC and the drive shaft is vibrating like crazy! It has been awhile since I've done a lift and it seems like maybe I should have rotated the axle to keep the drive shaft in line. But I just cant picture the leaf springs resting flush on the axle if I do that. Can some one help?

Front shaft you think? A 1" thick spacer on the transfer case front out put shaft flange may help, you also need to check for clearance at the transfer case flange (double cardon joint) the later model 44 front axles have the most pinion angle as part of the housing design. Have you made sure the shaft is in phase? hope this helps.

Generally, when you go over 3" of lift, you tend to run into driveshaft problems.

Do you know which shaft is causing the issue?

You may need to fab up a spacer for the transmission/transfer case and install it on the transfer case cross member. Or as an alternative, you can try an output shaft spacer as suggested above. Good luck!