Stu, do you actually measure the CR with the burette whilst the head is on/

I can't work out how you can do it propperly that way, on a CVH head anyway.

If it was a Cossie or Zetec, yes, fill to the base of the spark plug thread and thats about right (but not perfect, due to the plug not being there).

But on a CVH head, where the sparkplug is mounted off centre, and not at the top of the combustion chamber, I don't see how you can CC it that way? As if you fill the combsution space with water (or whatever fluid your using), it will not propperly fill upto the roof of the combustion chamber? It would spill out of the plug whole long before then?