https://www.enginediy.com/products/diy-engine-model-double-cylinder-engine?currency=USD&utm_medium=cpc&utm_source=google&utm_campaign=Google%20Shopping&gclid=Cj0KCQjw9YWDBhDyARIsADt6sGYQZV4k89QQDDnQQ6iM BUY96bgk0NGYxXhPXnUCAqox4cKRH7CT-AkaAou9EALw_wcB
Here's a link to the same engine from a different site.
It has a more realistic price tag, but, the same poor english writeup,
and, the same loose overhead cam tower someone didn't tighten the bolts up on,
So I don't know if the first one was too cheap, or this one is too expensive (or combination of both).
cool engine though!