I have a 89 K5 with 4" TC springs, ORD shackle flip in rear, SX8000 shocks, and a 10 degree shim. When we did the lift the pinion angle difference was about 10 degrees. I still get a bad vibration from the drive shaft in the rear above 20mph, and especially when decelerating. I wanted to know from anyone who may have done the same type of lift combo what degree shim they used and if they did anything different. Just gathering info before we dive deeper.