I think with a FAST, you might go over the 400rwhp mark with a good tune. I've got long-tubes, cat-back, VR, SLP 1.85 rockers and a ported intake with a best of 397rwhp/387rwtq SAE. My ported intake didn't give much in the peak department but good gains in the mid-range. Another fellow has the same mods but I think the rockers you've got, the FAST and made 407rwhp and about the same in torque.