Good points, Carl!
I've reconditioned a truckload of Cummins, Detroit, and John Deere rods, along with thousands of rods for gasoline engines. The average tolerance is less than .0005" in most cases. Unless the rod is round, and the right size, there's just no way the bearing will ever fit the crankshaft right. On the really high-HP engines, I've gone to the extreme of mixing and matching individual rod bearing halves to get the oil clearance I'm after, but that's really too nit-picking for street use, or a stovebolt restoration job. I did see one of my engines survive several laps of cycling between 9,500 and 10,000 RPM one night when the driver got the transmission in the wrong gear by mistake. No lower end damage whatsoever! We swapped rod bearings on that engine and ran it the rest of the season.
Jerry
