Now, is that the S-trim with a GT impellar? I'm seeing 12.8 lbs of boost. I can't recall off hand where my timing was set, but the a/f is 11.9. I know we backed the timing down some to keep it "safe" (as much as you can anyway with the stock bottom end).
Timing is just as important as the a/f ratio.
Make sure that in high RPM you are not leaning out....mine was going up to about 12.9 the last 1000 RPM's, so we added the boost-a-pump to solve that problem.
Also, one word: GAS!! You want to run high octane gas. I'm running 94 octane with a couple gallons of 110 racing gas mixed in (added safety from detonation). I also go to the same gas station each time so I know the gas quality is consistant.
Yes, it is the GT impellar. Worked out really nice. We decided to swap to 03 Cobra Dual Fuel Pumps & Fuel Tank because Walbro 255 is just plain pathetic and was not keeping up, so new dyno numbers will be next Wednesday after 03 setup installation. Fuel pressure was at 60psi, but dropped to 30psi after 5500, so we let out. However, I did make 433rwhp before the fuel pressure took a dive at 5500rpm. Power band was still climbing. So I am guessing around 475rwhp or so.