Pinion angle

I know every car different probably but what do most run pinion angle at. I have a 70 swinger with a 833 4 speed and 83/4. It was vibrating at 60-70 mph and the pinion angle was not set right. I ended up putting 4 degree shims making angle now about 2 and 2 between rearmed and driveshaft. Still has a vibration. Maybe not as bad?