67 Barracuda Manual Steering Question
Standard manual is 24:1 (I think it may be 24.5:1, actually). I don't think 16:1 was available as an option in 67, but they are interchangeable. It would be massively harder to turn at a standstill with any kind of fat or sticky tire, though I am sure it would be fine at speed. There are also 20:1 manual boxes available, which would be a compromise. I have standard manual steering on my 67 Barracuda. It is a handful trying to get out of a parallel parking spot, and it is too slow to keep up with the road in the real twisty bits, but it is basically fine overall, so I would agree that yours needs some attention.
If it's too tight, it's likely that the grease has congealed inside your box. Cleaning it out and repacking it may be all that is needed. I do not know how much trouble that is — I''ve never tried it.
When they are worn out they get looser, not tight, so adjusting it is probably not the answer.