Bored for .050 over pistons (which measured a perfect 3.4875). Our new boring cutter is exact - spot on. The old cutter liked to bore .001 oversize, which is fine - just so you take that into consideration. I like to give a .0015 to .0020 clearance on these newer cast pistons. The old (oem) cast Harley pistons were probably a bit more porous, (more air space in the aluminum) so they expanded less, and you might get away with a tighter tolerance - like .001 to .0015. Make sense? Now I'm confused.