robot is correct and so is brianurpnow!

To add to this topic...you simply need to understand the intended use of a panhard bar vs. the use of a dampening unit to know which one (or both) you will need.

First, when splitting a wishbone and using a dropped axle, you will need (and want) a panhard bar. The panhard bar keeps the axle located and prohibits sideways movement...thus eliminating or minimizing bumpsteer.

The dampener on the other hand...doesnt control the axle movement. It helps control the side-to-side wheel movement. I have one of the SO-CAL dampening units and it does help. With a Vega or Unisteer cross-steering unit, any bump can increase "road feel" to the driver. Four-wheel drives usually have a dampner to reduce steering wheel movement when driving over bumps, rocks, etc. While they arent cheap (only $35 in black...but $70 for chrome...) they do help minimize sideways movement of the wheels.

So if you are asking for advice...If I was building a new rod, I would certainly install a panhard bar. And I would add a dampner if I could afford it and had the room within the chassis. I would also recommend a stabilzer bar, other wise known as an anti-sway bar (Chassis Engineering makes one for the 28-34 dropped axles). With all three of these technologies at work for you, your hot rod will drive and act like a high dollar sports car!