8.8 swap
I have not set mine up yet but heres my idea that's been running through my head. It may seem like a lot of steps but it will ensure the rear is square and centered with a proper pinion down angle.
1 New polyurethane bushings on both ends of the leaf springs including on the rear bolt in mount.
2 Bolt up leaf springs at the front but do not super tighten the bolts. Leave them relaxed to pivot.
3 Set perches in place on the springs, and set axle on them.
4 Loosely install U bolts and shock plates so they are loose enough to move the axle side to side in the perches, and allow the springs to bolt up at the back end
5 Jack up the rear and install rear shackles. Fully Tighten the spring bolts tight front and rear to square up the springs.
6 Now you measure and adjust it side to side until its centered. Then tighten the U bolts snug to hold everything. Do NOT attempt to drive the car this way. This is only for mocking up the axle. I plan on spraying the tubes with blue machinest dye before I set it in place. Once I get the side to side measurement set in place, I will scribe a mark into the dye right exactly where the perch is against the tube so I know where to set the perches.
7 take the rear back out and set on saw horses and set perches on scribe marks.
8 position perches and axle with degree protractor to set a 5° down angle from square to the pinion
9 tack weld the perches in place and double check the 5° down angle.
10 weld up solid.
11 crack a beer and enjoy.