It sounds like the geometry used with the original box and steering required less travel. It may have even intentionally had less wheel travel as not to over-extend the axle joints due to IFS or other reasons. What that means is the piston stroke in the box is too short to meet the full throw of your new 60 and the style of steering geometry it uses. A longer pitman arm may give you the added throw you need, but it will put more torque on the sector shaft. I'm not familiar with the box, but there could possibly be some internal stops that can be removed or relieved to give it more piston throw, thus more sector shaft rotation. I would not add the ram until I had a box that would travel to the wheel stops. The ram will continue to try and push the steering even after the box has two-blocked, putting a lot of stress on the rod ends. If you can't get a longer stroke, shorten up the wheel stops.