i have just taken my head off and there is marks in the bore like swirls where it looks like it has been bored out. I measured the bores and it says its 80.5mm. Is this an over bore? if it is what cc will it be.

cheers

 

80.5 is an overbore and the swirls are honing marks. Quite normal.

 

would you know what the cc has changed too?