Valve Cover sealing problem with a stripped out bolt hole

Working for the railroad I've welded a nut on a stud like that a100 times or more and many times it was broken off below the deck like that. Not once did I ever have to drill it and use an easy out. Just use a nut the same size as the bolt diameter, hold it in place with a pliers or vice grips. It helps if someone can hold it for you. Then, striking an arc on the broken bolt first, just fill up the nut with weld. The nut will get red hot so you want to let it cool down a little before you put a wrench to it. A stick welder works best for this. If you have something broken off I'd try break it up and get it out first.
Try it, you've got nothing to lose.
Steve
Oops! I didn't see your post above.
Glad you figured it out