LS6 offers more passages in the block for better oil circulation, some will argue that the LS6 is a weaker block than the LS1 because they say the oil flow passages decrease block strength, i would concur this to be true in bored out blocks with forced induction creating more pressure and stress on the internals, but for most applications the blocks share similar strengths, LS6 had the better head castings with lighter sodium filled valves and stronger springs to support the increased lift (these figures would associate with the '02 and up LS6 setup, the '01 LS6 setup was very close to the LS1), of course the intake is improved over the LS1 allowing a less turbulent flow and the improved volume output of the LS6 oil pump, '01 LS6 cam had .525" lift and the '02 had .550" lift, the LS1 lift is substantially lower, as far as performance an LS6 cam offers outstanding numbers without giving away you have a cam if you want the sleeper approach, some people want the lope sound so it all depends on preference, duration numbers on the '01 are 207/217 and the '02 are 204/218, lower numbers on intake side with the '02 but increased lift overall, hope this helps...