Stock 6.0 truck flexplate, LS2 pilot bearing, and your current clutch will work for the SM465/LSX motor. It worked flawlessly in my truck before I exploded it.
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You should do some checking on this before buying into that advance adapters flywheel. Don't know if the 4.8 and 6.0 use the same flywheel (they both came with a standard factory) but I got my 4.8 flywheel from OReillys brand new for $50 and it bolts to the factory sm465 clutch. And the ls pilot bearing was the exact same as the one that came in my clutch kit for an 85 chevy.

