You might look to Hughes for a cam, I have used a couple of them and liked them a lot. They take advantage of the lifter size in a Mopar instead of using chevy lobes on a Mopar timed cam stick. A big rig truck store can de-arch your super stock springs if want to get a little lower, but it is a trial and error kind of deal to get the ride height you want. But it will not hurt the spring rate. Tubular upper control arms would make for a great investment, as well as the reinforcement plates for the lowers. Sounds like you will have a killer budget car when you are done! Good luck!