I'd look at the engine vitals first in regards to the vibration. All 8 firing, fuel pressure, engine tune, etc...
My stock LS2 makes 28-30 psi at idle hot. What weight oil are you running? Mast may loosen up their clearances and that could require heavier oil to get a pressure that makes you feel fuzzy. 50-60 psi at redline should suffice, hot.
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Todd
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