Aftermarket. I found them marked 453L 412 on one end and the other end is marked 453L KD. If you find any info on them pass it on. It'd be greatly appreciated.
I have a nice set of 1.06 A-Body torsion bars for sale. They were slightly used when I bought them and I put less than 5,000 more miles on them. Bars only, no boots, and bars are marked. Asking $150 plus shipping from 68301.