Wavetrac should be a direct drop-in replacement...I think it uses its own stub shafts, but it should come with those. 3.55s are also a drop in replacement assuming you have the correct kind - should be for a Dana Super 44, or Dana 44HD (8.9" ring gear diameter). The stock carrier and pinion shims will likely not work, but any master install kit should have different thickness shims to get you where you need to be on pinion depth and backlash.