I parted out a 67 Firebird 400 years back that only had 1 bar on the pass. side non-posi.
However it had a bracket on the drivers' side for another bar.
I still have the traction bar along with all hardware and those 2 axle brackets I cut off.
Steele has the rubber for them.
https://www.steelerubber.com/tractio...per-70-2293-35