I had read in the reviews prior to purchase people said these do not fit ? apparently they bought them for another application thinking they would ? because these fit NPI heads PI heads as well as 4V cobra/lincoln heads ..apparently they bought them for coyote heads by mistake ? also more then a few complained the nuts were staked ? these are oem header nuts you want staked nuts so they do not loosen once torqued down that is why the factory nuts are nearly impossible to remove. they are designed that way to prevent exhaust leaks. you can remove them and re use them but then you might need to use loc tite on them making them even harder to remove. you get 10 in a box you only need 8 so every 4 boxes you get another heads worth for free.