The specs you are looking for just don't exist. Usually, the ring gap can be as small as a few thousandths when the engine is warm, but we don't have specs on max liner diameter and min piston diameter. Those are usually quite inconsequential. You can usually tell that the piston/ring/liner fit is too loose if the engine will not idle and accelerate. You should be able to lean the engine to get a good top end.

The fuel you are using, along with the propeller will be more telling. They can dramatically influence how the engine runs. Your engine may not have ever been properly broken in, and so may just need more rich running for it to "come in".