What about metro soft seal ? I haven't had any issues with their stuff. I use them on both my 68 coronet and my 70 dart. You can go on their website and get the part numbers then check Amazon, I saved a bunch doing that.
I think you'll like it a whole lot better with a bigger rear tire under there. Those tires are tiny right now ! I'm very happy with my S/S springs in my '70 swinger