A better cheap way is to get a pair of coil over load leveler type shocks, you will get the lift you want without dealing with leaking air bladders, or having the lines break and dropping the lips of the wheel wells on to those wide tires I'll bet you'll put on next! You could gain an inch ot two using a set of shock extensions that bolt onto the lower eye of the shocks.
The best way,really, is to use
1) new EXD leaf springs(like what 340/big block cars had) or
2) a set of superstock springs, which will be a bit stiffer too , and a good investment if more power will be added later, or
3) if the springs you have are in basically good shape, a good spring shop can re-arch yours, or add some arch to change the body height, or even add an extral leaf, giving you a poor man's set of Superstocks.
The EXD or Super Stock springs can be gotten from Mancini Racing or any distributor of Mopar Performance parts, Even jegs or Summit Racing.
To re-arch yours, look in the yellow pages under Suspension.
Air shocks are really a pain in the ***, and the flexing they give the upper shock mounts can go so far as to rip the mounts out of the floor, or lead to repair work later. For what they cost, the springs are a better idea.
Another trick, have the spring shop put clamps on the leaves at every seperation forward of the mounting point for the rearend. This will help stiffen them up and help control axle windup.
Then, get or make an adjustable pinion snubber with the tip of the snubber 1/2" to 1" below the contact point on the floorpan.
Leave the "traction bars" to the Ford and Chevy guys, Mopars don't need them.
Alan627b
Extra heavy duty springs
http://chucker54.stores.yahoo.net/extraheavyduty.html
super stock springs
http://chucker54.stores.yahoo.net/superstock.html
shock extensions
http://store.summitracing.com/partd...1288&N=700+400330+4294804463+115&autoview=sku
pinion snubbers
http://chucker54.stores.yahoo.net/adpinsnib.html
I used to have a red/white 73 dart sport 340. Looks like yours is the color known as petty blue or basin street blue. Good luck with it!
Alan