Motor Mounts

I have bolts through both my mounts.
Driver's side has plenty of room, original bb car, here is a reference: Best Place to Buy Motor Mounts For my 383 Formula S.

I'm sure the countersunk bolt head helps.

I used the same method for the passenger side, iirc the only issue was I had to shave off one side of the bolt head on the top for clearance, which also helped to hold the bolt in place.
I found only 'controlling' the driver's side mount wasn't enough, as once I did the passenger side failed.
I have a tunnel ram so it was quite obvious when the mounts would fail. Once my driver's side was secure, the passenger side failed and the carbs were in contact with the hood.
Imo, the engine isn't technically lifting on the driver's side, it's twisting.