[Bill Eveland]

69f bird, I would think your angle at the trans sould be positive-lower at the rear. When the pinion angle rises on acceleration your probaly almost 4 degrees in differance between the pinion and trans. You almost need to raise the angle at the trans 2 degrees (drop it down so it's level)or drop the pinion angle 2 degrees so they match better.
What was your working angle of the u-joints? With the car level and u-joints vertical, measure the angle of the driveshaft . Than subtract the angle at each end.