First off I would check to make sure all the brackets are square on the new housing. Then pull the front R.S. ladder bar bolt to see if it has preload (with driver in the car). It should with the weights you have posted. You have access to scales so I would start by equalling weights on both rear wheels. I also feel that 3.5 degrees is to much pinion angle. 1.0-1.5 should be enough. Provided the car now goes straight traction can be fine tuned with shocks,tire pressure, and possible ladder bar front pivot location. If not add slight preload opposite of the direction the car dives towards at the stating line. Also changing the front torsion bar tension will load the opposite rear wheel as well. When scaling the car, roll it up on the scales on a level area, don't jack it and slide the scales under.
Good luck Doug