And there it is, it looks like we've gone full circle and as such you'll probably have to buy a full Helicoil kit, but it will be enough to do every 5/16th thread in that engine. The sad part is that the Imperial sizes are more so being sold from the USA and the UK where they seem to be far more expensive than metric counterparts that are commonly sourced from our new Mother country.............China.
Cheers,
BB.
