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.
I'd suggest super stock springs and a stock K frame since it's a "budget" build. If you were are planning on getting in the mid 500+ HP range I'd suggest cal-tracs. After market k frame stuff is nice, but pricey too. As long as you can find stock stuff cheap I'd go that route, if you can't than save your $$ for an aftermarket k frame. Strut front end would be idea, but would take some fab and $$, but not really needed unless you plan on going fast.