OK so I picked up a OS 55 with a p-box and also got ahold of a OS 46 FX picked up a prop today at the local hobby shop got me a 12.25x 3.75 should work good on either engine think i'm going to setup with the OS 55 and give it a go see how it does that way . why do you say the OS 46 FX was a better setup ??? just wanted your thoughts before I actually get the engine installed as you might have a very good reason behind your suggestion I got time to deciede have many other planes to work on thru the fall and winter