Sirio goose - I used a Sirio #7 in Texas at the Nats (only ran 20% fuel). Mostly use a Sirio #7 unless you are using 30% in 90+ degree weather - then use a Sirio #8.....

MikeBtc3 - The origional Sirio engines did have wear issues but that has been completely sorted now. I've run the same engine at the Worlds, a local club race and all of the ROAR Nationals - approx 5+ hours of use and the pinch is still tight enough to push the sleeve out of the case when you turn it over with the head off!!!