This "piston slap" thing has been blown way out proportion and dragged from board to board by the same group with their own agenda, whatever it is.
I have a 2500 that has "been rode hard and ..." - doesn't guzzle oil, doesn't knock and I am the only smoker of the pair. Maybe it has to do with my breakin policy, the 8100's are hauling loads all over the country and drag racing occasionally
If you want an education on the 8100, and what it is made of check this standard 8100 vs the marine version
"Finally, and of prime importance to boaters, both versions of the 8100 were engineered with an eye toward durability. In fact, GM?s marine-engine standards surpass those required for its truck applications. In one test the engine was run in 60-minute cycles?wide-open throttle for 55 minutes, then idle for five minutes?nonstop for 300 hours, far exceeding the use the engine might get under normal operation. " - the time was to refill the tanks
BTW, 5300 folks don't read this.