5.3 dead start timing 2002 vs. 2007

superwagon modded the HP Tune on my Z66 yesterday. Man what a difference. Played mostly with the WOT timing and the off the line timing. The fuel tables and MAF calibration was done last time. Also uped the RPM's to shift from 1-2, and from 2-3. When we tested before the shift change I was hitting 4th at 81 MPH, after the change I was hitting 90.

Still struggling with the dead stop torque. Adding some timing made it better but its not real responsive at a dead start; We bumped it up to 10, but started knocking. I believe we left it at 8. We looked at a 2007 tuned by someone else and it was at 15 degrees. Are the engines that different or was there something else possibly done to run the timing that much higher?

I am also running split exhaust Magnaflow 3" in, 2 -1/2" dual out. The 2007 has a  50 series with dual same side pipes out,  but don't know the size.