LS7 Cam/headers/11.7 low hp/torque help

Hi, first thanks for the help, I'm not going to pretend to be a tuner, just helping a friend who is having trouble with a tune on his car and I have some HP Tuners experience working on drivablilty of the tunes in my own cars with HP Tuners..

Friend's c6 z06, did a bunch of work to it and the numbers just seem soft...

American Heritage package #4 heads milled 0.030 (11.7:1 CR) <-- my guess too much compression? have tried fresh gas but not 100 octane yet
AHP Stage 3 (112) Camshaft
Core: Isky Racing Camshafts (271-RR,HR-817INT, HR-670-EX)
231/244 @ .050, .648/.646 lift, 112 LSA +1
Haltech cold air intake
MSD 8.5 mm Super Conductor Plug Wires
NGK TR6GP Platinum Alloy Plugs
Kooks 1 7/8? Primaries X 3? Collectors
Kooks 3? Mid Pipes with High Flow Cats
new lifters, timing c5r timing chain, all the goodies...

His HP and Torque #'s are about 50hp off my car with a similar cam (Katech Torquer 110), and about 40/40 off a friends z06 with the katech cam and no headers. But both of our cars have WCCH heads with .020 milled. We are up in the 22-24 degrees of timing in the same area of the timing chart. Target AFR's are similar, so I keep coming back to the 17 degree of timing?

Anything over 17 degrees timing up in the power band and it is hitting knock retard... I'm wondering if it is real from the compression or false from the headers? Or maybe we are missing something else? Attached are the tune and data log. Dyno chart, look at the green graph, 491hp/455tq

(edit having trouble getting the jpg dyno plot to come up...)

thanks- Dan

Attachment 93243
Attachment 93244

Since you have good gas in it force some timing in and see if it picks up power.

still have to get the "good" gas for it, only fresh 93 octane in it now, but I was thinking that for checking for false vs real knock.