[rhandwor]

You can go to Advance Auto and buy a spark plug repair kit. They cost $38.00 they come with 3 length plug inserts. They have a ream on the tap. It takes a 3/8 inch extension and a ratchet. Measure the thickness if this is a COP setup
it will take the long insert. As the plug sets in a well use an old 14mm plug with the washer removed to install the insert. Use red silicon to seal the insert. For the tool to swedge the insert get an old 12point socket put it around the tool and use something like a piece of thin aluminum sheet metal so it fits tightly. Then use an old extension so you can hit it with a hammer.
Note before you install the insert use a hose wrapped with duck tap inserted into the vacuum hose and vacuum out all metal particles.
Remove a valve cover and make sure both valves are closed so you won't get any metal in the valve seat.
They sell kits on ebay for $200.00 to $450.00.
Don't worry take your time if you make a mistake pull the head and take it to a machine shop.