How are they different from any other leaf spring in this respect? I would suspect something loose, like the shackle bolts, front spring bushing, U-bolts, etc. I mean how can the spring be floppy enough to shift during steering, but not give massive body roll?
Have somebody turn the wheel while you watch everything underneath.
A couple other long shots:
-Bad steering U-joint hanging up?
-Front driveshift slip joint hanging up?
I don't know, I just think I read that somewhere. It doesn't make sense to me.
The joints are good in the axle shafts and I've driven it with and without the front shaft with the same problem.
I've double checked the shackle bolts, u-bolts, center pins, and the hardware the holds the front spring hanger on and the rear shackle mount and they are all tight.
I'll just swap the springs and see if it's any different than with the 52's.

. I've seen the steering box moving on the frame and the frame flexing. Overall stuff doesn't always do what you think it does and those things will never get solved until you do know.
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