[351mustanger]

Heli-coils are not that great. They are a good option when damage occurs, but not something I would put in for good measure. The better choice is a time sert. It has a heftier price tag though. In my opinion, the part you are trying to repair is not worth the time and expense to fix. The aluminum that these heads are made of is very low grade. I would bet over half of the people on this forum, with this type of engine, have been in the same spot you are in now. I would look at it as knowledge and wisdom gained. Replace it and be cautious when replacing spark plugs. Also, the exhaust studs will pull out of the head if you over tighten the acorn nuts that hold the header pipe on. So when you repair or replace the head, don't get carried away tightening the exhaust up.