the 340 came with bushed rods from factory. the top of rod was not drilled from the factory. sunnen calls for .0005 to .0008 clearance on bushed rods. if you use looser clearance you probably will get rod knock!! what is casting number on the rod? last three numbers should be 496 or 645.
Yes, I have never run enlarged pin clearances.... never had any pin issues at 7000-8000 peak RPM's or turbo or anything, floating or pressed. Maybe some really high end blown applications or constant 8000-10,000 RPM's need it.