My rig turned 300K this morning:
No real major problems at all. Just normal stuff like several FSD's, one injection pump, alternator, A/C compressor, couple of starters, etc. Never touched the engine internals or even had to replace a glow plug yet.
I've owned the rig since 174K were on the clock. I think it had one injection pump during that time as well.
Casey
1995 K1500 Tahoe 2 door, 6.5LTD, 4L80E, NP241, 3.42's, 285/75R16 BFG K02's; 1997 506 block; Kennedy OPS harness, gauges, Quick Heat plugs, and TD-Max chip; Dtech FSD on FSD Cooler; vacuum pump deleted, HX35 turbo, Turbo Master, 3.5" Kennedy exhaust, F code intake; dual t/stats, HO water pump, Champion radiator; Racor fuel filter