Originally Posted by 1Gary
But I an still curious what you guys think was the one thing GM improved on the LS engines that make them perform as they do.
There are many things they improved, not just one. They improved heads, valvetrain, intake manifold, firing order, fuel and spark control, cooling, much more rigid block, better pistons and rings, etc.
If you're looking for just ONE thing then you'll never find it, the difference is because of many changes.