I just used 1 of the nuts I took off 1 of the studs to double nut the others, the stud that was frozen in the cover was so tight that the double nuts striped the end of the stud. I forced a 5/16 USS nut on as the last nut and using alternating heat and penertrating oil I was able to rock it loose.
Had to go to ford for the new studs and that was another ordeal, the original dealer told me he did not have them so I hit 2 other dealers. They did not have them but their computers said the original dealer I went to had 12 of them so back to the original dealer who it turns out was looking up the wrong part. He had them in a package of 4 so I reused 1 of the original ones, other than the one that broke they could have all been reused.
When reinstalling the studs some of them go into the water jacket and require sealer, the new studs had some red sealer already on them on the reused one I used #2 permatex