SS60 injector orings

I’d use the big o rings along with the small graphite crush rings on the bottom. It’s just for extra insurance. Crush graphite seals up the cups, which are often beat up a bit, from the injector pounding on them. You can usually see the damage. You can clean them up, but the surface around the hole where the injector sits will probably be distorted. You’ll usually see a half ring grooved witness mark Some claim the graphite cupped crush washers are a band aid. But even if it’s not needed, won’t hurt anything. It crushes very easy. Big fat o ring as it’s commonly called, gets pinched when torque d anyway. Doesn’t change a thing, just insures a better seal. Only other choice is to change the injector cups. They need to be pressed in from the bottom. I’ve heard some claim they can change them using a mysterious Special tool. Without taking the head off. Don’t know. I’d use both just for insurance. The graphite washer will crush to nothing, won’t hurt anything. Might insure a good combustion seal, avoiding a small leak from damaged cup seat. After running a while, I think carbon naturally builds up and seals them up good. If you had a new head with new cups, they wouldn’t be needed. I replaced 2 injectors on mine, used them on both. Had over 500k on one of them, before rebuilding. Didn’t use them with the 6 new injectors this time, since head and cups were new