Lower Control Arm Pivot Bushing

So I scanned this topic and although I might of missed it I did not see anything in FABO that addresses my question.
Recently I was rebuilding my entire front suspension, in the process I was doing the upper CA bushings , replaced them with Energy Suspension urethane pieces. I had looked at the lower CA's and the pivot bushings and as they looked very good decided to leave them alone. On second thought they were maybe 50 years old so lets put in the new ES parts.
So for all readers that have done this, even with a press it is a decent job. As per ES installation instructions I left the outer sleeve of the OE bush in the LCA and "pressed" in the new urethane one with the pivot shaft installed. Pressed means by hand!!!!

Here-in lies my issue. Simply , what holds the LCA on to the pivot shaft? If you are going to rely on the Torsion Bar I have to call BS. My torsion bars have at least a 1/2" clearance between the "retainer clip" when the TB is driven forward into the CA hex. I can't imagine that it will not loosen up after a few miles of driving allowing the LCA to slide back and forth on the pivot shaft. Am I missing something here or these things should be outlawed? I am going to go back to the factory ones, they lasted for the first 50 yrs on the DDart, unless someone can convince me other wise, which at this point is not happening.
One more related question. Can someone tell me what year in the 70's did Mopar change the strut rod length, thread pitch, and nut size? What was the reason?