new leafs pinion angle question

Well I got new XHD leafs on and the pinion angle changed slightly.. the car came up in the rear about 2.5".
Now my question is my tail of tranny is 1 deg pointing down and my pinion on rear yoke is 1 deg pointing up. I was hopping for my downward deg with new leafsprings.
So to achieve correct pinion angle should I shim the rear or cut off perches and adjust then reweld? The car is a 68 Cuda 383 4 speed. And I am having clutch chatter from dead stop. And recently I shimmed the rear and it made a big difference in the chatter. So I would like to get the proper pinion angle and hope the chatter is gone completely. . Thanks