Binary 01,

I wouldn't trust that mount at all!!!!! The bent screws will eventually snap due to stress.
You would be better off getting an adjustable, nylon, motor mount. The nylon mounts are good at reducing vibration.
Attach the mount to the firewall. Relocate blind nuts if needed.
Rest motor on the mounting rails and transfer hole locations from your motor. Drill holes and bolt through using appropriate hardware. I think 1/4 - 20 x 1 1/4 with locking nuts would work.
This will keep you and your plane safe and in one piece.