Unless you're building a blueprinted racing engine that's going to turn warp speed, a few thousandths of difference won't matter. I've always measured a set of rods to find the shortest one, and reconditioned all the others to that length. Then we would deck the block to get zero deck height, and balance the rods to a +/- 1/10 gram weight match. (A dollar bill weighs one gram). Then that $8K engine would last half a season on a 1/4 mile dirt track, cycling from 3K to 8K RPM twice a lap. Totally worn out (or blown up) in less than 500 miles!
Jerry
