run tests before removal relative compression, actual compression #, power balance, hpfp test, crankcase pressure test , fuel trims, and video of it running with good sound quality. once removed pull valve cover check rocker arms for wear and pull water pump for cavitation and check turbos for wear. If that is all good and documented 8500 all day. If there is problems price accordingly. I buy cores for 1000 bucks. Mileage is not an indication of anything on 6.4. current condition is whats important and proof is where the value is. video all the tests and it will sell fast