Leaf springs for dart swingers.

I lik to run the MP super stock springs ending with part numbers 002 & 003 on my a-bodies... They will lift the rear up 2 - 3 inched from stock height....

Or you can get a set from Espo Springs n Things and they can make a set that will lift or lower it to whatever spec you want... I've installed a set of those on a 71 Dart for a local member here and they were very good... when we had a problem with the shackles going forward vs rearward when lowering it, their customer support was there answering our questions within 20 - 30 minutes after leaving a message... They have great customer support and make good product...
I about freaked when I installed mine and the shackles were going the wrong way. A 4' pry bar did the trick! LOL