On alum heads? So basically 8.25:1 given how alum heads don't heat as well as iron. With that cam makes for a dynamic compression ratio of 7.52 (at 0 feet elevation, less is more, in my area that would be 7:1 dynamic). Which once again with alum heads is more like 6.52. Yeah sorry if this sounds rude, but that's just stupid. Mismatched components for sure. Pump gas dynamic on alum heads is in the area of 8.5. They are leaving a ton of power on the table in that build.