I just went through musical leaf springs and per Dr. Diff's recommendation ended up with 2 driver's side A body SS springs.
http://www.cuda-challenger.com/cc/index.php?topic=100088.0My car is running a fresh Edelbrock headed 440 Sixpack engine with Hemi 4 speed and 3.73 Dana rear end.
90% street driven but I do plan to take it to the track a few times a year with sticky tires.
The car seems to ride real nice and the car sits right where I want it to.
I wasn't expecting much traction with street radials but there is no wheel hop.
I'm very happy with my choice.
Here are the parts you will need, I got all my stuff from Summit Racing.
2 driver's side leaf springs Summit part DCC-4120080....this is the exact leaf spring part number Dr. Diff gave me.
1 pair of Mopar extended front spring hangers for SS springs Summit #DCC-3412003
A set of smaller bushings for the rear leaf springs to shackle, the rear eyelet on the A body SS springs is a little smaller.
I bought rubber Moog bushings (1 box of 4 will do the entire car) Summit part #MOG-K7309