We mini tubbed my brothers 76 Dart sport. Narrowing the fold down piece was easy and the seat it self fit like a glove. I'll try to get some pictures and post them later today.
Longer rear shackles will raise the rearend' but like autoxcuda stated the off set on your wheels more the problem. 295/55/15 on mine, stock spring location. 4.5 offset 8 inch wheel.
I used a art morrison kit. Fit good and retains back seat. Pic dosn't show it but rear bars follow roof and rear window and go through rear package tray in to trunk.
I had mine rebuilt localy. Don't know if you can buy a do it yourself kit. For what it cost to rebuild I should have bought new from firm feel or someone else.
I use caltracs with the split mono leaf and solid alum bushing.Very firm on the street but works well. I don't see why the rubber bushing wouldn't work but I'm no engineer.