Originally Posted by Hobbsy

http://sceptreflight.com/Model%20Eng...%20FA-120.html

The 1.20 that Clarence Lee tested here is similar to yours but has a different intake pipe mount, same carb and same exhaust pipe but he says its AAC. It must be a tweener model. You can see the step blow the cylinder, (in the crank case) that was done on certain models to keep the brass sleeve from sliding downward.