Two main problems.
Problem 1 is they keep loosening up. Not finger loose but definitely looser than the torque specs when I put them on there. I know you can't use loctite or a lock washer. I've heard about special locking nuts they make for some cars but I don't know where to get them and I don't want to wait for them to arrive in the mail. The stud goes into the head and then a nut goes on the stud to hold the manifold in place so I don't think doubling up on the nut would do anything. Any other bright ideas?
Problem 2 one of the stud holes stripped so I tapped it with the same diameter and pitch to repair it. It worked but the threads suck and the stud doesn't lose its play until it's 90% into the hole and I can see carbon escaping from this area on the gasket. So I think I need to retap one size up. But I'm concerned I'll run into issues with the larger stud being longer and not seating right. Thoughts on this?