I used replacement rear rails on my Barracuda and kept them "within tolerance", I would say.
Frame table with jigs would be best, a frame table alone would be alright, the method I used was sufficient if you consider how much these cars varied off the showroom floor and how compliant leaf springs are, it will work just fine. The bumpers can be adjusted out quite easily and that, and the springs are the only real major alignments that can be thrown off back there.
It was quite a bit of work but I feel it was worth it. Keep in mind that this is a "hot rod" build and hardly anything is going to be 100% "correct" on it.
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