the quality of the factory underbody was horrible "back in the day", and comparing your frame/chassis/unibody measurements to the measurements found in the FSM is sure to find your measurements are "slightly" [
] off !
as said, check for level and square, and for kicks, run some strings to the grease fittings in your lower ball joints to check the alignment of your front/rear suspension to each other.
THIS ^^^ BEFORE welding the boxes in!!!
When the 68 Dart 270 had the 7 1/4 with 155/78 13's it did not look like the axle was 7/16 inch offset to the right. But with the 325/45 20's you can tell real quick.
If I had known it would have been a bit of work but I would have offset the boxes 7/32's to the left side.
It is done and the easy fix is to offset the spring perch's and reweld them on the 8 3/4 housing.
