Firmfeel.com is the place for suspension pats. This guy has been around a long time and never heard a complaint about their producs, he is my go to guy. He is also a mopar guru who races his products.
The size of the bar indicates spring rate, and mopar 1.04 bars in a 73 Duster 440 with KYBs at each corner had a resonance from 75-85 MPH and this created a real nusiance.