Couple options,
You may run into clearance issues with the torsion bars, so if you were to remove them and go coilover (there's threads about that) then you might be better off (That's not replacing the whole front end...is it?

). Then you can do the removable cross member mod and not even worry about the torsion mounting points. If you keep the torsions, well they probably have enough capacity so just crank 'em till the ride height is correct again. That's why they are adjustible. Some things on '72 are different from all other years, but I do believe the front suspension is the same on all save the brakes. You should do the disc brake conversion, someone on here probably has a set of spindles to sell you or you can just covert the brakes over. Don't forget to get a newer master cylinder too. Most of the parts are available from NAPA Online for the later truck brake system, but the caliper mounting brackets and dust shields are not.