While the LS6 is a good intake, the manifold developed by FAST is even better. The engineers flipped the LS1 market on its head when it came out with the original 78mm and 90mm intakes.

While the intake is designed as a direct replacement for both the LS1 and LS6 intakes and looks very similar, FAST, with help from acknowledged induction artist Keith Wilson of Wilson Manifolds ...

After running the LS1 intake, we were curious to see how a factory LS6 manifold would perform. As in the previous test, the manifold was equipped with a 78mm throttle body.

We promptly ordered up one of SLP's LS6 Intake Manifold Kits and were ready to get started with the swap, so follow along as we add more 50-state-legal LS1 power.

In addition, the LS6 cylinder heads have slightly smaller combustion chambers that increase its compression ratio to 10.5:1 compared to the LS1's 10.1:1. The 2001 Z06 LS6 produced 385 horsepower ...