I didn't know the box mounted in same spot exactly, that's nice. As far as which column, I never really cared what length because I was using DD and ujoints and made it work without cutting column. If you do use a 60's column, you can possibly use Borgeson couplers with splined or DD shafts, with your rag, to adapt length. That won't be too much more money and you save a bundle on the column.
