Need help with 2 issues but same place!

The rear end! On my 1972 440 dart, i still have the original leaf springs. I believe they are just worn out because the rear end of the car sits really low. For the time being i have air shocks on it so it doesnt look so rediculous but i know its not a permanent fix. ALSO, i want to make the car hook up better. It is a street car but i want it to hook still. May take it to the track sometimes. Obviously it doesnt hook now with the 245/60/14's on the 5.5 inch wide ralleys with sagging worn out leafs.. I WISH i could have it mini tubbed to put some meat under the rear as i LOVE that look, but i cant afford that right now, but would like to stuff the most tire possible under it for right now. SO, what do i need to do to the rear of this dart to get it to sit up like its supposed to AND also hook up off the line? All help is GREATLY appreciated!