Steering column to steering box problems

I had my steering box rebuilt and finally got to putting it back into my 68 Dart GTS. Problem is I can't get the column to go completely down the spline shaft of the steering box. What am I doing wrong?

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Is the box bolted down tight? If so, try loosening the box then see if shaft goes all the way down. It just might be in a slight bind. Or you could loosen the firewall column mount a little to do the same thing I think.