How do I get taller install height?

I'm sure you have read about my 918 springs breaking. I hear that the 918 spring needs to be set up at 1.80 so I checked mine the best i could and it seems to be around 1.631. How do i change it so it will be around the 1.80? Is there differant shims i can get?

what did you check it with?

if really are at 1.631 installed height, the way to get more is to get offset keepers, offset retainers, .100 longer valves, or grind the valve pocket in the head deeper.