do i really need

Slant 6 torsion bars and no sway bar is the old DC recommendation for drag cars. Why? Because it keeps the front end "loose" for better weight transfer. Not optimum for street cruising.
I've done it and driven the wheels off of it- not great, but not my cup of tea anymore. I'd stay with your V8 T bars at a minimum. Add the sway bar later- you'll find one at a decent price eventually and it's a quick & easy job to mount it up if you've already got the tabs on your LCAs. The thing here is to plan ahead. Since you've got a Dana rear end, I'll assume you've converted the front to a large bolt circle, too- probably with the '73 and later A disc setup. If so, make sure you "rear mount" the calipers (just amounts to flipping the spindles and calipers to the opposite side, and using hoses that are a tad longer- usually Aspen/Volare or '69 Camaro pieces) to avoid interference with the pre-73 sway bar. Doesn't affect braking at all.