Im gonna do the same to my 75 dart eventually. Im also gonna delete them 75 shocks and do a solid mount I just gotta figure out how to fab it up. My plan is to use bumper brackets like you have pictured and fabricate it to work. One of my shocks are compressed so there is a large gap on one side and not the other. It's hard to see in photos but in person it's really noticeable.
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