You can lift the rear by using the older front spring mounts . The holes are only 1/2 but are a taller mount. You can also have them offset drilled I have gotten 3/4" out of a set. Get moroso rear adjustable shackles for the back of the spring.
Compare the holes with the studs in these pictures . The spring hangers you would need has the extra hole you see in the pictures
The second picture is the adjustable shackles. If you use them with good bushings they are stiff and good in turns.
1" to 4" Adjustable Rear Leaf Spring Shackle Lift Kit A-Body Dart Duster Valiant 768855330122 | eBay
For a 73 up you would need the larger bushings. Order a B-body shackle set. That is what I ordered to use with SS springs in the picture below.
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