engine mounting bolts

Hello, Just posting this clip I had of this terrible "engine" rattle I encountered mid ride a few weeks ago. This has already been fixed a few days ago but it might be helpful to someone with the same problem. I had the quad down to the bare frame over the winter time and when I put the engine...

Anybody know what the diameter of the engine mounting bolts are?... I used a micrometer and fount it was close to 7/16 so I went to lowes and bought some and came back and no-go!! they were too big... the next size down is 3/8 and i tried one and it seemed like it wasnt as snug as it should...