What suspension upgrades should i do for $1200 big block dart

Heck if you did all that the car would probably be lighter up front than a stock small block car.

You've already got a good start with the 1.03's. If you're running the stock leaf springs out back it would be good to upgrade those. It's not as dramatic a difference as adding the larger torsion bars up front, but it makes a difference. I'd go at least to XHD's, they're about 110 lb/in. But anything from 110 up to 130 lb/in would work well. I like the mopar oval tracks, but they do set the axle back a little further too if you run them with stock hangers (it's only a 1/2" at most). Other than that I'd go with a set of Bilstein RCD's and some sway bars front and rear. Tubular control arms are nice, but all you really need for a street car is the Moog 7103 offset bushings and your alignment set around -.5* camber, +3* to as much as you can get for caster and 1/16" toe in. You can get more negative camber and more positive caster with the tubular arms, but it would be overkill with the BFG T/A's. They'll be the limiting factor if you add the shocks and sway bars.
72 Can you tell me who sells the XHD`s