Vibration can't figure out where from

[Chevyboy12]

1978 k10 8 inch block lift in back , very bad vibration I have to feather the clutch so it doesn't just almost bounce off the wheels any one have any ideas ? Also my steering wonders a lot

 

[89Suburban]

You mean the clutch is acting up?

 

[philjafo]

4 inches is a lot of block lift, with 8 I would bet your getting axel wrap. Springs get weak if they are overstressed, for example if its been running an 8 inch block lift. Do you have 8 inch blocks in the front too? That could be a possible cause of the steering wander if it changed the castor angle on the axel.