RE: SURPASS-90 Pattern Plane - Has anyone heard of them before?
I mounted the engine directly to the hardmount of the plane, but raised this by adding some ply in between (otherwise it did not line up as well). To reduce noise and vibrations, I overdrilled the holes and used rubber D-locks to mount the engine. To ensure that consequently the engine did not fall out one day (I was not so convinced that the D-locks wil actually hold the engine in place overtime) I used longer screws which after passing thru the D-lock screwed into a plate. Hope this helps.
Here a picture of the engine mounted with the original screws supplied (this was before I replaced this, and added the D-locks). You can see the added ply.