Buy or wait , L 83 5.3

[bandit0067]

Guys, finally settled on a 'new' truck and purchased a 2015 GMC with "C" code , L 83 , 5.3 engine. Truck is in fabulous condition but with 200k miles. In my info search on the cylinder drop out technology used with this engine, it sounds like with the higher mileage engines this failure is inevitable . I have found a used, complete "C" motor with 39k miles for $1600. If I purchase this for a ' if and when time' comes , what would be the most defiantly needed replacement parts before installing. Im hearing the high pressure fuel pump seals seem to leak fuel into the lifter bay in time, what are your opinions....