I ran Ohio crank H beam 4340 rods in a motor. Broke the motor but it was an oiling problem. Windowed both sides of the block. Some of the rods were wadded up like lead. Wish I had taken some pictures of them. I've worked with alloyed metals all my life and have never seen 4340 that maliable. The alloy may have been correct but I am sure the heat treatment wasn't done properly. With just about any alloy the heat treat is the main process in the strength and endurance. My personal feelings on Ohio rods. I wouldn't run them in even a mild street motor.