@lubbockguy1979. I stand corrected on 450,000 on black onyx. He has 450,000 on truck and has the black onyx gaskets for 188,000 of that. I would have went the international or ford oem gaskets but my kit I bought came the sinister ones and asked the tech if I should purchase fords or international and he said no need as the black onyx ones will work just as good as the fords or international ones. And my kit was about $1700 for the arp headstuds, black onyx head gaskets, turbo gaskets, exhaust manifold gaskets, oil cooler, egr delete with new pipe and sct tuner. Didn't think that was a bad price. Probably could have saved a little bit here and there but I didn't have the need to place dead end phone calls all day or search the internet to squeeze a few bucks here and there. And by the way he puts about 1100 miles a week just to go to work at the dealership. Anyways from my understanding its all about your heads and what shape they are in and if the arp headstuds are torqued down in the correct order and lbs. And wow on the 1000 rwhrspwr. fuel mileage has gotta suck on those ponies. I am planning on going to o-ringed heads from Liberator but gonna do some more research before I jump into that.