front hubs free and transfer case in 2H shouldn't bother anything up front..
the biggest issue I've heard of were on the later, lighter duty front axles..
now positrac was GM's name for limited slip on Dana axles..
might have a D44 up front (both my 71 k20 and 71 k1500 do) and might be a little heartier with it..
was thinking about adding one to my k20 at some point but haven't researched specifics yet..
but the bottom line is, they'll all serve you well to get out of the mud but won't care much for 4 wheel burnouts
looking forward to seeing more of what's under there.. divorced transfer case would be icing on the cake!
found one in a GSA suburban with pto winch but guy wanted too much for it..