Sparkplug Hole Repair

[Rex]

While pressure testing the heads on my 45, I found that both sparkplug holes need to be repaired. The steel inserts cast into the aluminum heads are intact but the new sparkplug fit is very loose, and the threads in the inserts are visibly distorted and nicked. I was able to stop the air leak with a LOT of teflon tape.

What's the best fix for this?

[charlie frey]

Look a couple threads down at "UL spark plug repair."
Same deal.