I used the Redcat Racing alloy mounts on mine and it worked fine. I had to widen the holes left to right to get the gear mesh right but they line up the other way.
Check out urchobby.com for the engine mounts. Kurt is great to deal with and Im sure he can get them right out to you ASAP
Actually do you have the spur gear installed in the right direction?
If you zoom in on this picture you should be able to see the engine mount