I have also had the head bolt threads strip on my block. My machinist let me use a steel insert (much stronger then a helicoil). I forgot the name but it is a kit that has a block that is positioned over the hole(the block is held in placed by a bolt off another head bolt hole and is located by a tap that is inserted into the original hole) and then the defect hole is drilled out, tapped, and counter drilled. The final step is to screw the insert onto a threaded tool and apply red lock tight and screw into the hole. The tool is slightly inlarged the further up the shaft you go, so it will install the insert very tight.
This setup has worked for me on three different occassions with the engine in the car. Just tape off the other cylinders and the lifter area and use a magnet to remove the metal that might get into the water passage.
good Luck,
Jeff Rand
If you like call up my machinist for the name of this insert.
New Performance
714- 549- 0188 (Ca.)
**** New
