Valve Cover sealing problem with a stripped out bolt hole

Back during my Millwright years our machine shop had an EDM machine that could zap and break up broken ez outs and taps. You could check with local shops to see if they have one or offer that service. Once removed you could drill and tap a little deeper and use a stud. If the guy is good enough he could do it in the car. I had a engine deck welded in the car with the short block together and never missed a race. Hurt it Sunday and raced next Friday.