Front/rear suspension options?

Looking at a '71 Dart, no K frame or rear suspension. What's my options? MustangII? Straight tube? Or find a good K frame?
Are torsion bars the way to go, or swap to coils?
Stick to leaf spring rear? Probably use a Ford 9".
Planning a hot 360/727, maybe 400+ hp. Dedicated drag car.
Dedicated drag car I'd go with struts up front. Struts are lightweight, don't take up much room and will add value when you sell the car. They do a require a professional install but if you already have a full cage then it shouldn't be too difficult.