318 LA rebuild after losing a valve seat

If you have 2.109" + or - measured with 2 good measuring tools, then it sounds like the crank was turned wrong. Sounds like the .020" bearings are not going to do it either, but it is worth the try, plus checking the mic vs standards. (My mic's are ancient and still are within .0005".....)

Where did this crank come from?

^^^^^ Trying to remember if the actual size of the oversized .020 rod bearings are actually made to .018 to allow the .002 oil film clearance between the bearing and crank when assembled ??