The arguement used to be when the compression was lower, the cyl was larger internally even though the displacement was the same. With more room from piston to head, that left more room for mass, even at the same boost level. More mass can mean more cyl presure, just never seen it work out that way myself. I'd love to see logs if that theory holds true. The maf at the same rpm would show a higher frequency. Ading ice to an intercooler shows the same results. A maf reading would really help. Octane linited would explain it, but Coonsake was already on race gas. Coon, how are your inlets at those levels? What kind of temp rise do you see do you know?
I've seen maf lb/min go up with more timing more than once on my Whippled car. Often enough, and repeatable enough that I can't explain it away as a glitch.
Splain that one Lucy