I think the problem may be with those tubular control arms.

You could plot the caster, camber and toe change through the suspension's range of motion or replace them with a set of stock ones and see if the problem goes away.

There's not a lot of things to cause this. A balljoint with a tight spot in it or the box itself but you seem to have covered those bases.

You could take it to another alignment shop, don't tell them anything other than you want them to set it up on the machine to check it and see if their results resemble the readout from the shop you are using.

Kevin

Speaking of tight spots, did the drag link ever get checked?

It would help if we could combine the 3 or 4 threads about this

the draglink has been rebuilt, and has no play whatsoever.
in fact, every moving part has been checked multiple times, and there is no play anywhere in anything that pivots or moves up and down.
it's getting to the point where i think there may be so many aftermarket parts plus a mix of items that just "fit", that the basic geometry is plain screwed up.
someone suggested plotting the suspension curve, and i think that is a prudent move.
however, since the weather is nice, he is constantly on the go, and i don't know if i can get him to sit still long enough to pop the front springs out to really get an idea what is going on with the suspension moving through it's whole range of travel.
i am not literate enough to do a computer analysis of this. i need to see it in real time, then use measurements and some math to figure it somewhat close.
one thing i haven't done though, because it would take me some time doing.
i have all the "old time" home alignment tools. magnetic spindle mount caster/camber gauge, swivel turn plates, and toe stick. it would be interesting to see what i would get if i spent a day or two checking with my tools.

Just get it on the rack and align it. The way it is now is not right. In a few minutes after the caster swings are made you will see exactly what it is. Steering angle, thrust angle along with all the readings for caster, camber, toe. If it aligns to the specs I gave you then deal with any problems. If your friend is that busy he must not care about the issue. Neither should you if thats the case.

here is a pic of the last alignment done in august of last year.
i remember now it was mentioned the way the upper arms were mounted, [inboard of the chassis mounting point] all the shims were removed, and the camber could not be made any more positive.
this is not a constant "sawing back and forth" [unsafe] correction needed, rather just a minute thing that gets bothersome/tiring after a 3 hour drive.
of all the power steering conversions he and i have made over a 50 year friendship, this is the first one that has had this symptom/problem.
the vendor that supplied the box said this box is designed to be tight on center instead of having the minute play other boxes have.
tossing $100 bills to the alignment place every time isn't much fun, especially since i have the tools and know how to use them, although it is getting difficult to crawl around like i used to.

The way that print out is it looks like they did not adjust anything. One other thing I did not like is the included angle is less than the SAI angle and the included angle should be more. Again that car is not in line. If a proper alignment was done those numbers could be then in specs. Tell your pal to quit screwing around and get it to a qualified alignment shop.

The math checks out for the difference between sai and included angle, remember there's a ton of negative camber.

But included angle is close to caster which may be affecting directional stability.

Do you have the original control arms?

Also, back off the adjuster on the drag link, too tight can bind the steering. Its spring loaded and should have some (minimal) play.

I don't know bleep about 58 c-cars.
With the aftermarket upper tubular control arms currently made for Mopar, I think most can be swapped left for right.
If this is possible on this car, try swapping them.
The OEM B body upper arms, '62-'72 , actually have the upper ball joint offset slightly forward to REDUCE caster angle!
And as others have said, return everything to stock, and start over.

It's actually a 58 Impala. But good point about having the arms on the wrong side.

My '69 Darts, manual steering, max caster with stock suspension, the wheel would snap back very fast when turning fast in parking lots. Not so with my power steering car that have more caster than is achievable with stock suspension.

to be continued...............

based on what i see/read.... your cross member is sagging. this was very common on those cars. you most likely cant get enough adjustment to correct your camber. moog used to make a [ 2*] shaft /bushing kit to correct this. .usually all the shims are out and you have no more room for adjustments ! to fix it , you chain it down on a frame machine and pick the center up to get it back to specs. your toe should be good at 1/8" in and your camber should be positive on both sides not negative.to start get it around .5 pos right and 1.0 pos left . this is for radial tires....the camber split keeps it true on the slanted road.. caster is not the issue... check it and let me know . i am 99% sure this is whats going on.... Does the power steering box have the directional assist valve on the bottom? thats the only other thing i can think of that would do this...

Positive camber????

WOW,

yes . positive camber... to the op. check the things i asked about and let me know where they are.... then i will re-think what i have posted... i dont think i am wrong and this will clear it up quickly. nobodys perfect ! i stand by my words... this is a rear steering car correct ???

Positive camber is fine for old school with narrow bias tires non handling goals. Negative for everything else.

It's an unusual problem but I've dealt with the same thing on 2nd generation Explorers. Excessive negative camber from the frame rails twisting inward. My only concern with such a diagnosis in this case is the aftermarket control arms and the possibility that they are not correct for the application.

this is a front steer car.
a trip to the frame machine was mentioned quite a while ago. i think the age, plus the botched air bag mess, has the crossmember ginked up.
went looking for the original control arms a couple of days ago to check their lengths against the tube arms, but i believe they may have been scrapped.

Just align it and see where it takes you. No sense overthinking this.

But, he can't get more camber. Getting less caster should be doable but camber will go more negative.

Have the knuckles changed too? Or just the arms?