I just ordered my first quasi War Bird - a World Model's Dago Red. I currently have a OS46 with a pitts muffler to put in it. Is this going to be enough horsepower to fly it I don't need to go 120mph but 90 or so would be fine.

That should be adequate power but I doubt you will see 90mph. The plane is designed for the 46 size engine (72 4S). I have a 72 4stroke in my Yellow WM P51 yet I have heard of people put 90 or 100 4S in it too. that would be like a 61 2S size. Fly it with the 46 which will be good and then you can go bigger if you really get the need for speed. It's a great plane.

I have the standard WM Mustang. I have flown it for the last two years with an OS46FX, Saito 72 and now a Saito 91. I sold one to a buddy last fall and he is flying his with an OS46 FX with a pitts. You will like it!! The 46FX does a real fine job. Props can make a large difference in the top speed so experiment to see what works best for you. I always start with APC brand.
Fred B

Hi Fred. Thanks for you input. I think I will try the 46 first and see if it has enough guts.
Mark

there has been many post on this,most in the extrem speed prop section.but i think that the 46 will fly it fine that is what is is made for