Are my torsion Bars Weak? '65 Dart

A short list on new ones.
Firmfeel http://www.firmfeel.com/torsionb_a.htm
Summit http://www.summitracing.com/parts/DCC-5249151
Jegs http://www.jegs.com/i/Mopar Performance/312/P5249151/10002/-1?CT=999
Mopar Performance

You will need to figure out what diameter you need.