Racers have been polishing connecting rods for years to improve stock rods durability and to decrease weight. The benefit to polishing is that you remove the source of potential stress fractures.
All factory rods have ridges from the forging process that run the length of the beams. This is the weakest part of the rod and most likely the first place a crack will develop. Our high performance Cummins 5.9 rods start with the early tongue and groove rod core (not late model cracked rods) they are inspected for flaws, cleaned, and magnafluxed next the beams are ground, polished, and shot-peened, new high performance rod bolts installed, resized, checked for straight and balanced. They can be used in the common rail engine to replace the cracked rods. (Cracked rods refers to connecting rods made using powder metallurgy, The cap is then separated from the rod by a fracturing process, which results in an uneven mating surface due to the grain of the powdered metal.) Sold in matched sets only. Core charge may apply.