If your going to wheel it then the skids Butch (4x4iron) sells is the ticket. The frames are so narrow that getting any of that tube stuff to work is a pain. Usualy what happesn is you drop onto the sikds and then the suport bars hit the rockers and bend them up.
www.off-road.com in the chevy section has a Write up Glenn (Depdog) did on project RocKready when he made a set.
When I did mine on the 75 I welded a vertical on the slider and ran it up into the A-piller and blind nuted it in. It added a lot of regidity to the fire wall. Off all the roadster K5 I have rode in mine has the least cowel shake and I have budies with fairly rust free 69-72's