I think what you are proposing is certainly doable. If you know going in you'll have substantial unsprung weight with that large center section and tubes.
I would plan to build it as a full floater. You'll need new axles,axle stubs and all the outboard hubs and brake units. Just make sure axles can be made to match your differential and to the hub.
I built a full floater AMC 20 for my Road Race AMX using all Moser pieces. The GM 14 bolt should be a piece of cake compared to an AMC! The Moser stubs are designed for a three inch tube. I believe the 14 bolt is probably larger, so you might have to machine a ring to enlarge the Moser stub to fit your tube. I had to machine the stub down for the AMC.
You'll need to do some quality fit up work and welding to ensure correct dimensions on the finished product. Depending on your usage you can also dial in some camber or toe-in if you desire. One thing about the full floater is you don't have pad knock back issues. Like I said as long as you can deal with the weight, go for it!