I replaced my whole front suspension a few months ago, including a new steering box. I was hoping it was just tight because it was new, but it hasn't loosened up any. The effort it takes to turn the wheel is fine, but the wheel doesn't return to center by itself when I come out of a turn. Could it be the adjustment on the steering box - I could try loosening it, but I thought these were bench adjusted and I don't want to mess with it if there's something else that could be causing the problem.
Thanks,

sounds like you might have a very simple problem. Had your car aligned yet? The motion your describing is the effect of the caster in your fornt end. It's what allows the wheel to turn. It is possible when the arms were reinstalled that the caster could be near zero or even negative. You want more positive. Quick ex. If your upper and lower ball joints are directly in line vertically, that is zero caster. The farther forward the upper is than the lower, you have negative. Positive caster is the opposite. It is very hard to eye up so take it to a good alignment shop and have them look at it. Also, if you have them, try to get the specs, the shop may not have them.

I posted my alignment specs after the rebuild. Only got one reply saying "not bad".
I just replaced the entire front suspension on my '68 Elkie and got it aligned. After searching for posts here, here's what I asked for:
Camber neg 1/8 degree,
Caster 3.5 Left, 3.0 Right
Toe-in 1/8".

After taking out all of the shims, here's what I got:
Camber neg .030 Left & neg .070 Right
Caster 3.49 Left & 3.33 Right

I was told I can't get any more negative camber and can't adjust caster without shimming, which would make my camber worse; so I'm stuck with what I got? Should I be concerned with these specs, or are they close enough? I suspect I'd have to go to offset shafts to get any better - would it be worth it?
Before the rebuild, I tightened my steering box to see how much play I could get out of it. The feeling I have now is similar to the one I had when I tightened the box too much.