'74 Duster suspension suggestions

Thanks for the suggestions. So you guys think those coils are not original equipment? Everything else on this car looks pretty darn original. Even the leaf springs looks original and saggy. I just didn't know they used coils and leafs.
The competition engineering adjustable shocks look pretty good. Anybody with experience with them.
Player1up, I live out on Lake Mary Jane near Moss park which is near the airport. I get out your way to Speedworld a few times a year. Usually I am running my yellow Z06 corvette (11.50s with a darn 2.0 60' at 128mph...someday I will get it to hook and get a 10#). Our goal for the duster is a 12 sec # on a 318. My nephew and I are going to try to set it up and do most of the work ourselves. Thanks!