The below pictures are a 1974 F250 4wd (highboy) converted to 2017+ rear leaves (Skyjacker FR173S) and a 2005 Sterling 10.5 axle. I originally had a more level pinion angle and I had a small vibration at 40+. Changing to this more upward angle and minimal u joint angle fixed that vibration and this truck is now freeway friendly as pictured.