has anyone removed the box & have any tricks or advice?

 

Welcome to CF!
Tricks? Well.....a gear puller to get the pitman arm off of the steering box shaft. Use some penetrating oil too. Sometimes they need a little help to break 'em loose. Light taps from a brass head hammer will helppersuade it to move.
Hope this helps!

Oh ya,.....take the pitman arm retaining/clamping bolt all the way out.

 

what is a good place to send the 61 box for reconditioning

 

Ya might try....
www.ecklers.com
www.mamotorworks,com
www.zip-corvette.com