FYI, the helicoil kits for the 10mm plugs are very expensive. I think the thread is 10 x 1.0. It's a bit of an odd ball. I bought a kit and it was $90. A good investment if you need it in the future, but for a one time repair it's cheaper to buy a new head (that is, if they are in stock). With that said, I have a lot of leftover helicoil insert from the kit I bought. If you get in a jam, PM me.