We ran the Arrow engine this past weekend at the Indoor Canadian Shootout and it ran strong all weekend long. The ambiant temps were in the 30's most of the weekend and the engine was a little rich due to breakin and the temps and the engine was still getting close to 10 minutes of run time so when this thing breaks in and the temps come up to normal racing temps in the summer, I bet this engine will be in the 12-13 min club all day long. The engine was flawless. Not one single flameout and the carb held the same needle settings all weekend long and was a rocketship to boot. Very impressed with the performance and ease of tune. The only thing to prove is longevity.