You should look up some of Jim Laroy's (IQ52) low compression engine builds. He's proven time and again low compression can make power. And I mean like 7.35:1. you don't have to go that low, but you don't need race gas either. From one compression to another is only like a 3% increase all things equal, so it's not all in compression by a long shot.
If that's the static compression ratio, wouldn't that bring the dynamic compression ratio to 6.0 or lower? Isn't a dynamic compression ratio of at least 7.0:1 needed to make decent power?