Great stuff guys. I have been running nitro trucks the past few years and have forgotten how much different the fuel mix is for planes vs. trucks/cars. Won't be using any of thatose fuels for my Fox's and such...

I just found an old Fox 35X? It has a square bodied carb and an aluminum insert. I believe it is a combat engine. Are there any other identifiers that would help me find out if this a Fox35X? I also notice the wedge on top of the piston looks pretty tall. It has a lot of compression.