Thanks guys. I am in America so we still have a tendency to think in inches instead of metric.

For some odd reason my metric rulers have all been misplaced, and I couldn't find them, I am sure they'll show up now that I don't need them.
Ok I remeasured things, the bore looks like it was coming out closer to 22mm, as I could get about 21.96mm fairly consistently. I measured deeper down inside instead of at the top.
I don't have a depth gauge so measuring the stroke to 0 to 0.4mm difference is not going to be easy. I redid the measurments and using a 64ths of a inch ruler, I was getting about 53/64ths of a inch or a hair over 21mm. My eyeballs just can't see that tiny well anymore. Trying to descern 0.4mm is tough with a ruler much less using 64th's of a inch graduations.

So then all the Green Head engines were .49's or 8cc then? When I was looking for info, it seemed the head colors were more or less random.

Oh yeah, there was not head gasket or even a shim on the head button. Did they run them without a head gasket or shim? I don't have a problem with using no nitro or low nitro fuel.