Stripped sparkplug threads

[grannyknot]

Just found these guys, looks well thought out.
http://www.timesert.com/

[SlowOldGuy]

I put a set of TimeSerts in the head of my '85 when I pulled some threads removing a plug (never use Never Sieze on plug threads even if it says High Temperature). 

The TimeSerts are a neat concept and the kit comes with some cool tools.  However, installation of the insert wasn't as simple as the instructions lead me to believe.  I almost trashed my head when the insert got stuck about half way inserted.  I had to improvise the rest of the installation using the cutting tool.  But once I learned the trick, the other 4 inserts were not problem.  I bought extras to do my '93 one of these days.

Do not attempt to do this with the head on the engine.  Way too many metal chips produced in the process.

DavidR.