Cylinder head bolts for RZ250

[Antman]

I'm fitting a new head gasket to a RZ250 engine which I've had for a couple of years. I have lost the head bolts. Are these a common size? The thread is M8, the stud hole is 13mm diameter, and the nut needs to be around 15-20mm deep. Your advice would be much appreciated. Ant

[Magua]

Try a local wrecker? I managed to pick up head bolts for my bike and it's even older than yours.