There are suspension upgrades that can be done to make a truck not handle like a truck. In the case of the '57 Chevy seen here, the owner brought it to Kevin Francis at KA Custom in Huntington Beach, California, because any time he drove around a curve the rear tires would rub inside the bed to the point the paint on the wheelwells was burning off. The handling characteristic that caused this problem is known as excessive body roll, or sway, and is cured with an anti-sway bar. Don't get confused when you hear someone has installed a sway bar, and think they installed it to increase sway, it's just the anti portion has been dropped from the part's description. Beyond curing tire clearance problems, the main idea behind installing a sway bar is to improve a truck's ability to corner flatter, which means it will be able to corner faster, which means the truck will be safer and a lot more fun to drive.
In a perfect world when a guy buys a classic truck customized by its previous owner there should be a master list included of every part installed complete with its brand name and part number so replacement parts can be found when the need arises. In the real world, as with this '57 Chevy with a Mustang II type frontend and air ride of unknown origin, attempting to install a sway bar to fix a problem meant a way to adapt to it would have to be devised. As a starting point to equip the '57 with a sway bar Kevin and Steve selected one from Total Cost Involved intended to bolt directly onto one of their Mustang II type frontends.