Sub frame alignment?

[bsharpe]

I spent a lot of time trying to align the subframe on my firebird. It is not easy with these cars especially on jackstands. I understood that my unibody was not perfect (the pinch welds are destroyed and she has been hit), the ford 9" and 4 link isn't perfect (I didn't measure enough when I installed it) and my subframe has some issues but I didn't expect to run into major problems and spend as much time as I did.

I used a laser level and old vinyl tiles under the jackstands to level the car. I then plumb bobbed from everything that was symmetrical on the car like holes in the frame and the pinch welds. I used a chalk line to find the center line of the car. I then squared the rear axle to the body by taking cross measurements and wheelbase measurements. I then tried to square the subframe to the rear axle. I was unsuccessful and found major issues with my subframe. I am now evaluating my options.