We set this one up with the complete correct 68-71 stock mount set, because it looked stronger and more forgiving with the rubber mounts above & below the tower...and they have a steel plate at the top & bottom with a big bolt & sleeve in the center.
This is a built 454 and ran a locked spool in the rear, so the torque was pretty severe. I think I need a longer "Test Pad" for these BB trucks!
NOTE: I do have one set of 72 BB MM that I just got. I will sell for: $150 + shipping, if that will help anyone.