[MPKind]

I’m going thru the same issues. Vibrations at 60-70. Just installed new rear arms. Uppers are adjustable. More upgrades coming. But just with the new arms and an improved pinion angle, the car vibrates less than before. Still tweaking things after the initial setting.

As for doing the angle thing. It’s very simple. Zero the angle tool on the DS. Engine is “nose up” 2-3d from DS. Pinion should be “nose down” relative to DS.
2-3 d. They should sum to zero if you’re using a broken back aka W pattern. Or if using a Z pattern they should be equal. Where trans shaft and pinion are parallel. Most low riding older cars use the W pattern. They should be as close as possible.

The nose