I would love to hear from someone who has actually done the tube swap.
The tube swap isn't that bad, but you must drill out that big 'Plug Weld' or tack weld as I call it next to the carrier housing. Its the round cast sectiond of the housing right next to where the rear cover bolts on. Most of them face rearwards. Look before you leap, some folks will weld the tibes to the housing around the axle tubes, check for this....
Usually, I hust drill them out up on my fab. table with my magnetic base radial arm drill. Did last 3 with a big bertha hand drill, wasn't bad cause I kept my drills sharp and cool. I just drill thru into the tube.
Then, I slide in a piece of metal inside the tube outside the housing area. You can do this, just slide a piece up in to the axle tube and give it a good, heavy tack. I have a rear end holding fixture I can put onto my big motor stand, so its standing straight up. I install a bottle jack, bracing agianst the other side of the housing, and pop the tube out. After the 'Plug Weld' is removed, it don't take alot of pressure.
Some axle tubes are straight, some are bottlenecked down Some have 2 or 3 stepdowns on them, just depends.
Don't go cutting your axle tube willy-nilly, cause you could be faced with a step in diameter.
Look, use your head and plan. I replace alot of tubes on race stuff. They are lighter and stronger than the origional cast sections. Sometimes you can pick one of those units up cheap cause someone is going to a diff. housing. But, since you already have a good housing with disc brakes, If I were you, just cutting the flange off the rear, making sure its back on perfectly straight would not be hard if you pay attention to details, then reweld it. Just get everything aligned correctly, tack things good @ 12, 6, 3 and 9 o'clocks. Then start stitch welding around.
You can always adjust your rears look with wheel offsets to bring body clearance in or out....
