Well, if it's a strong 61 RE you may want to try something in the pattern world such as a WM Zen or Tai Ji. Both are made for rear exhaust engines have the pipe tunnels already built into the plane. Both of these are excellent fliers and I'm sure you like the way they handle. I have the Zen 120 and couldn't be happier.

Zen
http://www.theworldmodels.com/para/p...?airplaneid=40

Tai-Ji
http://www.theworldmodels.com/para/p...?airplaneid=40

That's my recommendations in the ARF category. Good luck!