Sloppy manual steering

[69skcharger]

I'm hoping to confirm what I think is the cause of my sloppy steering in my '69 Charger. All steering components and ball joints are new, steering coupler is good. I removed the steering box and adjusted the worm gear following the procedure in the manual - it was a bit loose, so that was promising to address the steering feel. The sector shaft adjustment was done by feel before installing back in the car. Once reinstalled, the steering was terrible, so I little by little adjusted the sector shaft and it got better, but the adjuster screw is flush with the lock nut, and there is still slop in the steering. SO... Is it fair to say the steering box is just worn out and needs to be replaced? Or, is that much adjustment in the sector shaft pretty normal and sloppy steering is just the reality of a 50 year old car?

I just don't want to spend $500 on a new box to end up with the same steering feel.