Piston dia vs cylinder bore.

I am sure this question has been asked but I have not seen. How much bore space can your moly ring take up? I am looking to replace my beatup Ross pistons. The pistons are listed 4.375" When I take actual bore measurements it measure closer to 4.380" 4.378" on average.

Is .002" to .003" difference the norm? I’m sure there are rings that can support a wider gap, but what is best practice?

Reading thru tech pages opinions vary. It appears a drag race motor may want a little wider gap then say a circle track motor where operational temps are more constant.

And does ring thickness play a role? Or does a thinner more expensive ring just offer less friction?

I’m not sure we wish to add ring end gap to the discussion. This topic may need a few threads on itself.

Please feel free to think outloud.

I am sure this question has been asked but I have not seen. How much bore space can your moly ring take up? I am looking to replace my beatup Ross pistons. The pistons are listed 4.375" When I take actual bore measurements it measure closer to 4.380" 4.378" on average.

Is .002" to .003" difference the norm? I'm sure there are rings that can support a wider gap, but what is best practice?

Reading thru tech pages opinions vary. It appears a drag race motor may want a little wider gap then say a circle track motor where operational temps are more constant.

And does ring thickness play a role? Or does a thinner more expensive ring just offer less friction?

I'm not sure we wish to add ring end gap to the discussion. This topic may need a few threads on itself.

Please feel free to think outloud.