Neon spark plug thread repair help

The threaded insert doesn't have to go all the way thru into the combustion chamber. Make the threaded hole and leave 3/16 to 1/4" of material at the bottom of the hole to support the valve seat area. The plug should screw all or most of the way in there. It may not be as efficient as it would normally be but it will work for a long time!! Without more pics of the other side (where the plug seats) I can't offer anything else. A car that runs at 95 percent is better than one that doesn't run at all!! Also....would it be wise to use some Loctite so they don't come loose???