Hiya Paul,
Just as a World-beating stunt design alone wont take you to the winners circle, a world-beating engine wont either. Just as a good model takes time at the stick to become a winner, an engine takes a fair amount of tinkering and expiramenting. There also seems to be allot off double-talk by people reguarding engines. People complain about the lack of CL engines on the market, yet when manufacturers come up with one, very few people buy them in favor of what is available in the cottage industry. Build a quick-and-easy profile, buy one of these "snorers", and start the R&D process. Fuel, props, NVA, venturi's, ect. are all tools to bring engines to life. It could take awhile--a season or maybe two-- to find the right setup, but its worth it in the end if you come out with a sweet-running powerplant.