I'm out of town but I don't mind taking more pictures for you. The stock setup on a 360 is a 530 chain, if you were to buy an O-Ring 530 pitch chain it would interfere with the clutch actuator and cause problems down the road. The 520 chain is less weight and more delicate, making the rotational mass less when accelerating and giving the engine more bang for the buck. If you are going to buy another primary chain to replace the stock one from 197x you're much better off with this setup.