Thank you for providing that info.
The nominal size of the piston is 75mm, the number of the piston crown giving the exact diameter of that component.
For example, if the number stamped on the crown is 0.956, it indicates that the actual diameter is 74.956mm, or 0.046mm below the nominal size.
The actual bore size of a standard cylinder is stamped at the bottom of the related bore. For example, if the number found is 007, the actual bore size is 75.007mm.
The piston-to-bore clearance can be calculated from the two above examples.
In this case, it would be 0.053mm clearance.
Thank you for your inquiry,