Stripped head stud- new Hardware?

[Wrench]

i ordered these for an '80cc' engine so i suppose they're 8mm, branded cdh. https://www.ebay.com/itm/195438796292?_
6mm studs of different lengths are on amazon though https://www.amazon.com/dp/B083TZ5M19?th=1
be sure to buy from a good seller and site that offers guarantees and free returns.

May 6, 2022

Solved.... I was wrong... again... the studs on this small 50cc are 6mm. I went to the hardware store and bought a 3 foot 6mm threaded rod. Cut it to length with a hacksaw. Oiled it up and threaded it into the bottom end. Put the head on with some flange nuts I also bought, torqued it down took it off the bench went for a ride. It is fixed and started right up. No leaks.

Do I need to re-seat the rings since the jug was off? I ran it twice for about 4 miles each ride today

Thanks for the input from the group.