Originally Posted by jrb55gh

I read your whole thread. Getting verifiable results to prove your concept with minimal investment is a tough assignment. But you did it. Thanks for all seeing it through to a usable conclusion.

I compared your 23 degree timing with the datalog on my stock 2013 7AT with ECUtek tune and noticed that my max timing at full throttle is 29 degrees. That timing does not knock on my stock 370 with clean combustion chambers. The reduced 23 degree timing required for your 80k mile test vehicle may be the result of deposits in the combustion chamber causing hot spots and/or raising the compression ratio.

Somewhere in the thread you mentioned verifying flow through the manifolds on a flow bench. That is a great idea. Some cylinders may be receiving more flow than others, running leaner and knocking. If you can adjust the porting to make the flow equal to all cylinders, you may be able to crank in more timing and unlock more power.