What does cc'ing a head involve?

[sp_cs]

My car currently undergoing a topend rebuild. Then engine builder said that the heads 'cc'd at 89.8' - what does this mean exactly?

Also said my CR is 10.45:1 (euro spec + some machining of barrell to head face)

Any thoughts please?

[304065]

Bouffant hairdos, Miranda, Grace Slick and THESE HEADS

89.8 must be your combustion chamber volume.

I think 10,45:1 means you should have twin plugs if not already installed. Milling the head is not a good way to increase compression ratio.

[sp_cs]

thanks John!

Car is single plugged, but I'm guessing 10.45:1 is borderline on a RoW UK based car, even with 98/98 Ron fuel.