You can, seems like a lot of people do not though. http://www.jalopyjournal.com/forum/showthread.php?t=199148&highlight=model+steering
You can also re-position the box further back on the frame. Then just shorten the steering shaft/column, and install a new, longer drag link. However most of us get rid of the stock model A box because they're just not very good boxes to begin with.