do i really need

a sway bar for my street car? also got a pair of 6 cyl torsion bars. do i put them in or stay with the v8 ones? building a 71 dart, 360 magnum, factory fi and computer. dana 60 w/3.54 and 904 lock up. this will not be taken to the race track at all. just a fri/sat car to go get ice cream. i have a pair of lower control arms with sway bar tabs but no sway bar. do i really need the sway bar? i guess i could add bar later but... what say you? tia. rick w.