This http://www.flyinglindy.homestead.com...struction.html is what I did with a pair of Ryobi's that I converted using Jag http://jagengines.com/ conversion parts.
The aircraft got dorked but not due to the engines. Repairs are under way and the same motors go right back on. They spool up so evenly and smoothly.. I've converted a couple more for single engine airplanes and will do more in the future..
The guys at Jag treated me great and I like the cast motor mount...