I have been working with the NGH 38cc Four stroke gasoline engine for two months now after a lot of peaking and tweaking to get rid of a lot of vibration. When I first started the engine would have flown a separate direction from the plane there was so much vibration.
I have got this engine to run as good as I can. Can you guys that have mounted and flown with this engine check out the video and tell me if the amount of vibration is not too bad to install this into a plane without a disaster.
Here's the link:

http://youtu.be/88JDgtFkuUo

That sort of looks like a lot of vibration. But I remember a few of my engines could vibrate my engine test stand apart. But your engine mount looks a little small to me. I don't remember them making big 40cc engine mount rails for RC engines. So it may be the engine mount causing the problem by flexing too much.

But I wonder if the largest Dubro anti-vibration engine mount for 1.20 four stroke engines would work with the NGH 38 engine or not. There were or are some other ones that might work as well. I remember one that had large rubber donut inserts that you could use with a regular engine mount. You had to drill larger holes in the firewall for the rubber inserts. But it would work with many engine mounts that way.

Perhaps contact MTK, I'm not sure if he still does but he used to make mounts for people. They are a soft mount which absorbs some of the vibrations.
Not trying to criticise this engine but many users complain about excessive vibes, it's something you are going to have to accept and deal with the best way you can.
Have a chat to MTK.

I got these anti vibration motor mounts with the CMP P40 Warhawk check them out -

Those do look pretty interesting. Do let us know how it works out.

I went with Hyde soft mounts. I used them on my 120" Grumman Widgeon, hasn't flown yet....will be early Sept.
Before anybody comments, the line coming off the crankcase vent terminates at the carb, so any oil ejected from the vent will go into the engine, not all over the outside......seems to work. I have about an hour on each motor breaking them in on a Great Planes giant Ugly Stick. Before I added the Hyde mount, I thought the Ugly Stick was going to shake itself apart.....it didn't!
I'm thinking of using that vent tine to add some lube to the cam before each day's running, after a few runs with the engine inverted, the cam and lifters were pretty dry.

Cheers,
Dave.