thanks. they are gmc style-easily converted to work with ANY tcase, not just the one included in the sale. my experience(i swapped gmc's for top loaders) is the gmc is lighter, requires less lift to fit. i had 8 inches of lift with the gmcs-everything fit with a BDS 8 inch kit. when i swapped out the gmc to top loader i needed more lift to clear the top loading diff to oil pan, then the drive shaft hit the trans pan on compression, so next was a divorced tcase which then required a new trans, and a trans crossmember cause the front shaft hit that too. oops. the only benefit i see to top loaders is pinion brakes, or wheel mounted disc brakes(which may swap to gmc's, i'm not sure), and slightly more clearance at the diff housing, unless your going nuts with aftermarket upgrades(lockers, axle shafts, etc).
I like to think of the gmc 2 1/2 ton as a BIG dana 60, lol.