I have done this on a old head to experiment with. I drilled all the way through into the the cylinder stud hole. . Then I taped as far as I could, stopping short of the cylinder itself. Didn't want the tap to bind. . There is about 1/4" more to be used. Coated the stud with (I use red) lock tite. Install a cylinder bolt where drilled, screw the stud in to the cylinder stud and back off about 1/4 turn, and let sit at least overnight, 24 hrs if you can. I used a drill press and made a jig for the cylinder jug. I've also aluminum welded the hole, drilled, and cut new threads. Works like a champ.