Thanks for the compliments on the car, guys. The camera hides a lot of flaws. But, for a High School car, it's works fine. Door dings are gonna happen. He can drive it and not panic if he gets caught in the rain.

The rear tires are probably a bit too tall. I got a screaming deal on them and the wheels, so I bit. I think they are 255/60/15's off the top of my head. They are almost new, so when they wear out, we'll get a smaller set. Of course, I hope that takes awhile.

One item of note. I had the front end originally a little lower. I put the tires on it and had them balanced, the new weights are larger. They hit the upper a-arms. So, by raising the height a little, I got them to clear. All I want for Christmas is a tire changing machine and a few tons of good old fashion lead weights!

As several have posted, adding a leaf may be a cost effective fix. One full leaf at my local spring shop costs $100 and change and increases height by about an inch... stiffness also.

Less cost than Eaton, but still good selection and quality are leafs made by Stanley Springs in Harrisburg Pa. Contact them for a local supplier. Otherwise, see what shipping is from Stengel Bros.
http://www.stengelbros.net/Leaf-Springs_c_177.html
At the bottom of the page is a link to listings of springs available by application.

Having gone the helper spring route as a greenhorn, allow me to suggest ditching them at the first opportunity. They really are best for situations where there is extra weight being carried in the rear. They make the rear stiffer (in the upward direction) and in doing so make the car more likely to fishtail and spin.* This is worse at higher speeds (like a highway to highway interchange) and slicker conditions. Don't ask me how I learned this before I understood this...

You can get a little more ht in the rear by cranking up the front. Factory spec on front ride ht for Dart/Valiants is about 2 1/8" IIRC. That's from the bottom of the t-bar anchor to the lower ball joint. If you change the ride ht, then reset camber, caster, and toe in that order.

Leaf and coil springs do lose rate and hieght after 75 - 100,000 miles. Quicker if abuse (overloaded, raced with stickies) and longer if only driven on smooth roads by super smooth driver weighing 95 pounds. Also the interleafs wear out, but those and the clamps (bands) can be replaced.

*edit: With extra weight on the rear, the extra spring rate won't tend to cause fish tailing. One method trucks and utility vehicles use to get best of both worlds is have a bottom leaf whose ends hang in the air until there's a bunch of weight in the bed and the leaf pack flattens enough to touch.

i would leave re-arching off the table. if you are going to spend any money, it might as well be towards a new set of springs. if you have the time and patience and can get another set of used springs super cheap that might work OK. but all in all a new set of springs is the way to go. i have bought 3 sets of springs from ESPO, i am sure the others are fine too. OEM mopar springs sit almost flat for a stock ride. this is because the spring will have the least amount of "sway" around turns.

I just bought new springs at the local Chrysler-Dodge dealer for a Big Block B-body. Mopar Performance ( or whatever they are now called) still sells them for a little over $100 each. Check your local dealer see if they still sell A body springs

Thanks guys. rm, I'll pm you.