True 264.... this phrasing does not make sense.. its either 264 or not.
264 degrees of duration, 272 degrees of duration, or 280 degrees of duration..
Dealing with the JDM/Euro market cams are measured at .010"
In the US most cam grinders measure cams at .050" which is more accurate of a number.
So although a cam with the duration measured at .010" and has 264 degrees of duration, if this same cam was measured at .050" the duration would approx be about 225 degrees (if you are speaking directly of subaru turbo cams).