On my engine, I had been able to get a heli coil threaded into one of the holes. We took that coil out, used the time sert tools, and were able to cleanly get the time sert into the hole. Took only 5 minutes, and worked great.Time-serts require a counter bore (which is the second step referred to) prior to threading the hole for the insert. I don't it woul work if a heli-coil had already been inserted and then removed. Might be able to be cleaned up with a thread chaser well enough to put in the insert.
Installing a stud in place of the head bolt would not be legal under Briggs 206 rules.
Studs are legal in the B&S rules
For headers, but not for a head bolt.
Wow... in a 2 page thread about header bolts, I guess your post is technically correct, but irrelevant. I, too, assumed we were still talking header bolts and studs.