Well we won't get in trouble for hijacking the thread if we talk about using E85 in those Cox .049's now. I wouldn't even try it. There, that was easy. The only thing I found works in those motors is lots of NITRO in glow fuel and an electric starter! At least 25% nitro.
I have one of those .049 Mustangs, it's a shelf model only, it does look cool with the head sticking out at a 45 degree angle downward. Do post a pic when you get the Lil Satan done. -Tom