Later versions were variants of the LS1. The LS6 featured redisigned cylinderheads, a new plastic intake manifold, and a camshaft with increased lift and duration. Some also featured titanium valves. The factory horsepower rating was 385HP on some ZO6 Corvettes, and later models were rated at 405HP. However, testing has shown that the real output of the engines are higher than their factory ratings.
The LS6 is found in Z06 Corvettes built between 2002 and 2004.
450hp Megacube V8 found mainly in older Chevelles, Corvettes, and even some El Camino's. Good for speed and acceleration, not necesssarily handling. That's right, you Euro geeks with your Porsche can **** off and die. Unless you can respect our cars, we won't bail you out of WWIII! Deal? Anyway, blah blah blah, the LS6 is a great old muscle car engine and is famous throughout the world, etc.
My '70 Chevelee SS454 was just barely beaten by my buddy's '70 Hemi 'cuda. He made it to the finish line .2 seconds before me. Of course, his car weighs less.