towen

I need a explanation on how the two piece trailing arms work on my 80' SC. (They are the type that consist of two plates joined by concentric bolts). I want to raise the rear of the car by about 1/2" and it looks like the way to do this is by small adjustments to the torsion bar (using combination of inner and outer spline changes), and then fine tune with the adjustment on the trailing arm. Is this correct?? Any other suggestions to gain that 1/2" ??