Yes, long story short, after replacing pistons, decking block, surfacing heads, the engine builder used a thin head gasket and that's what the compression wound up at.
Not to beat a dead horse, but what pistons? You/someone would need to have purchased a domed high compression piston which are normally reserved for racing. You cannot mill 906 heads and deck the block to 11.2 CR with a typical replacement type piston.
Not sure, I let the engine builder buy them and that's the CR he told me. I can tell you it doesn't like pump gas!!
Neither does mine, lugged in 4th it sounds like a paint can on straight pump gas. However it takes so little to get it to stop. 1 gallon of race stuff to five gallons pump quiets it right up.
