With aftermarket pistons, the ring packs that are supplied are typically what is referred to as a 'file fit' ring, which are rings that are supplied in an oversized form and it's then the engine builders task to file and correctly set the ring gaps for their specific engine build. If the end gaps are set too tight the rings can end up butting together as they expand from heat causing critical engine failure. If the ring gaps are set too large they can cause excessive blow-by, increased oil consu