[blucar]

Sway Bar: (track bar Panhard Bar) A bar usually attached to the rear of a vehicle that makes a solid connection between the axle and the frame. Common on coil spring suspensions.
Roll Bar: Common on front, rear coil spring suspensions and modern vehicles with parallel rear springs.
The purpose is to control body lift/roll on turns, the bar is connected to the frame and axle via movable links in lieu of a solid connection.
Ford started to use Sway Bars on the rear of '46-48 Fords/Merc,s, roll bars on the front starting on the Delux '40 Fords.


Pix attached of the '48 Columbia under the rear of my '36 with a factory sway bar.