And just for comparison sake..here is the factory rear suspension design (basically at least) My diff, which is a 9" now, and the different upper arms, but factory lengths and angles. Lowers are factory that I boxed.

Again, OE had to package everything for an everyday car, I think longer upper arms would have helped some from what I read.

But again there are better ways to go if you are building a setup from scratch so to speak.