I have 2 NIB Super Tigre .51 Ring engines. These are a far superior power 2 stroke glow engine where you want a .40 sized plane to excel. Each engine has stock muffler AND a NIB Slimline Pitts muffler(worth $40). They were going to power a Royal 310 but I decided to go with electric.
$99 EACH shipped CONUS.
Super Tigre's details: http://www.supertigre.com/engines/supg0154.html
Stock Specifications: (These are manufacturer specs and may not necessarily reflect the specs of the item for sale)