head bolt, or head stud

Depending what threads you find in the case, you might have problems finding a bolt long enough. It's been my experience that the case threads in most engines, 2 stroke Chinese, is a 1 thread. You'll need a bolt nearly 6 inches long with a fine thread. Most of what you'll find at fastener suppliers will be a 1.25 or a course thread when the bolts get that long. I searched at speciality/metric suppliers here in Denver and their catalogs didn't show a 6" length bolt with a fine thread. That'll be the rub.

Retapping the case might be an alternative but not advisable. There isn't a lot of 'meat' down there to work with.

There have been discussions here before about stud threads. From what has been reported there are studs with a fine thread on both ends and there's some with a course thread, both ends. Every engine I've worked with/owned has had a fine thread, 1.0 thread in the case and a 1.25 on the top, cylinder head end. Others will argue this but I can only report on my experience so far. My engines have come from three different suppliers and one unknown source.

Tom