A Jett 50 in a Class 2 MO-1 placed 3rd Place at the NATS a few years ago. It was a perfectly reliable engine with a K&B idle-bar plug, reverse-rotation crank, APC 9-6P prop, open exhaust and 25% nitro. Very easy engine to run. The JETT 40 and 35 also ran very well in Class 1 and Profile MO-1's. Perhaps not quite as fast as Nelsons but so-o-o-o much easier to make idle since Dubb sets his engines up to use a standard plug and the K&B idle-bar is a perfect match. Check with Dubb for reverse-rotation cranks if you think you need one. Pusher prop sizes are limited though.