Calcomputers, I have the .61 FX and I used the stock mounts. You have to shave some of the meat off of the inside of the mounts and trim down the "trusses" that run from the vertical bars down to the engine rails. It took a while to mount the engine because I didn't want to shave too much off the mounts. Dremel, fit, dremel, fit, dremel, you get the idea. I was starting to get a bit concerned about how much material I had to remove but it works fine.

I did break my first set on a perfect three point landing: 1- left wing tip, 2- left main wheel, 3- spinner. Can you say, STALLED IT!. I picked up a second mount and did the same thing to it. It has many flights on it and still going strong.

You will love the .61 on it. It's a blast!