full floating wristpins vs. pressed wristpins
I built a 440 using the honed out stock rods right on the wrist pins. I had holes with like the picture above in my rods, also holes in the bottom of the pistons- as well as the correct clearance. Keith black pistons with spiral locks. I had to tear it down for an unrelated reason and discovered all the wrist pins were turning blue and most were locked onto the rods. The engine had only run for maybe an hour. I wont be doing that ever again.