I chased the threads and used longer bolts in the somewhat stripped head to remedy the problem. Seems there is quite a bit of additional thread beyond the length of the standard bolts that hold the rocker arms in place. Both rocker arm bolts torqued up to 13 ft. lbs, so I'm going to leave them alone for now...
I have on order an M8 x 1.25 tap and a 6.75mm drill as well as some M8 to M6 thread inserts that are 20 mm long just in case they are needed. They install easily with a screwdriver. Thread lock can be applied.
After doing a little research I decided against the helicoils because they are relatively short and because I didn't like the idea of breaking the installation tang off and having it stuck in the blind hole. This would leave the option of using longer 6mm bolts to provide more torque a likely improbability.
The Time-sert bushings seem a little too expensive and they are short as well. I think I have a good option with the 20mm long thread inserts. Should be easy to drill out, tap and install if needed.
