It is all about intended usage. 318 and 340/360 use the same material and forging. What do you think is different, other than a bronze bushing on the small end? .
318 rods have a totally different beam size. 318's are tooth picks compared to 340-360 340's are full floating pins 360's are pressed pins . I have a **** load of 340 rods and 340 forged cranks. all taken from good engines switched to strokers. If using the larger rods Balancing is closer with the forged crank due to the journals being drilled. My son does balancing but the pistons , rings , bearings and pins must be sent. He also reconditions the rods
