Compression Ratio 1.1 engine

Hi, I want to increase the compression ratio of my 1100 engine.
I've calculated a 8:1 ratio… anyone has lowered the head? how much?
the formel e has 9,7:1…how is thifferent the head from gg?

skim the head and deck the block and have cutouts put into your pistons…

or go with the easy option and just put new pistons in : )