I made 445/412 with the G6X3. I have ARH headers, 3" exhaust with Magnaflow round mufflers. At the time of the cam install and dyno I had a LMR cold air intake, I now have a CAI intake with the ADM scoop. I also have 4.10's. Keep in mind I was dynoed at around 6000', so I think the numbers are better at sea level. I did not make it back to the dyno this year before I put her away for the year, but she feels much stronger now with the CAI and about 8000 miles. With a good tune and 4.10's this cam drives very smooth and the lope is incredible. I am very happy, I may port my heads this winter and see if that picks up a few more ponies. Good luck.