QA1 level 2 suspension kit: 67 Cuda.
The 67 A-body k-members have a lousy stud mounted idler. Expensive to replace and less stable than the through bolt 68-up style.
So at least you got rid of that. And you probably needed large UCA’s and LCA’s with sway bar tabs.
K-members, LCA, and UCA aren’t typically considered wear items. But they can get messed up from poor repairs and neglected maintenance repairs ruining the hard parts connected to them.
Inspect your parts.