ccing a head

You can use your piece plexiglass, just smear a little grease on the face of the head all around the chamber you want to cc and press the plexi onto it until it seals all around, you can see through itand you can tell when it's sealed. Then get hold of a 100 cc burette from a medical / chemical wharehouse and get a plastic one, you can get glass but they only need a small knock to break them.
Then fill it with some sort of liquid, [ I use trans fluid ] and drain the trans fluid into the chamber, when it's full just read the burette and it will tell you exactly how big your chamber is. The burette has 1 cc graduations on it and these are graduated again into 1/10 of a cc. Good luck.